After pleading guilty to a two-count information charging him with aiding and abetting an aggravated robbery and conspiring to commit burglary, appellant Scott Duffy was sentenced by the district court to two consecutive terms in the Wyoming State Penitentiary. His sentence on the aggravated robbery count was for not less than 24 years, 11 months, and 29 days and not more than 25 years. The minimum term for the conspiracy count was not less than 9 years, 11 months, and 29 days; the maximum was 10 years. Appellant was to begin serving his first Wyoming sentence as soon as he completed a Colorado sentence which he was serving when he committed the Wyoming crimes.
Appellant maintains that the district court violated Wyoming’s indeterminate sentencing statute when it separated the maximum and minimum sentences by only a single day and when it failed to give him credit for the time he spent in the Fremont county jail awaiting trial. He also contends that the court abused its discretion by basing its sentencing decision on ill will toward defense counsel. Finally, in an issue raised for the first time at oral argument, appellant argues that the consecutive sentences were illegal because the two crimes merged.
FACTS
The following facts were presented by the prosecutor at the sentencing hearing, and appellant conceded their accuracy. At about 2:30 a.m. on July 4, 1984, appellant’s grandmother, Ada Johnson, was awakened by the sound of breaking glass at her home in Lander. She went to the front door where she was confronted by Richard Sweaney who forced her to open the door at gunpoint. Sweaney made her take him to various parts of the house where valuables were stored. In an empty pillowcase he collected a diamond wrist watch and other jewelry, a .38 caliber handgun, and her purse. He then forced her out of the house, walked her to the edge of her property, and fled to a waiting car driven by one of his accomplices, Michele Frey.
Appellant, Sweapey, and Frey planned the crime over the telephone while appellant was serving time for a Colorado burglary conviction in a halfway house in Castle Rock, Colorado. Appellant told Swea-ney how to enter the house and where to look for the valuables. He also encouraged Sweaney to take a firearm. After the burglary, Sweaney and Frey were to travel to Colorado and help appellant flee the state.
The police foiled the plan by apprehending Frey and Sweaney soon after the crime. Based on their confessions, a criminal complaint was filed in Fremont County on July 6, 1984, charging appellant with one count of aiding and abetting aggravated robbery under § 6-l-201(a), (b)(i), W.S.1977 (June 1983 replacement) and one count of conspir*756acy to commit burglary under § 6-1-303, W.S.1977 (June 1983 replacement). The prosecutor filed a detainer on April 29, 1985; and, in early June, the Colorado authorities allowed appellant’s removal to the Fremont County jail.
Appellant initially pled not guilty, and the case was set for trial in December. He changed his plea to guilty, however, at a hearing held on November 14, 1985. At that hearing he waived his right to a pre-sentence investigation; and, after the prosecutor and defense counsel presented the relevant facts, the district court sentenced him to the consecutive terms outlined above. The court explained its sentencing rationale with the following statement:
“I want you to know that I have considered all of the factors to be considered in the American Bar Association Standards of Criminal Justice with reference to sentencing. They’re incorporated in this proceeding by reference, each and every one of them. I specifically find there are no mitigating factors applicable to this Defendant. I find the offender the leader of the criminal enterprise; the victim was particularly vulnerable. The victim was treated with cruelty for which this Defendant should be held responsible. The offense involved threatened violence. The Defendant is in need of correctional treatment that can best be provided by the sentence to be imposed. He deserves to be punished given the serious nature of the offense. There’s an undue risk if a lesser sentence were imposed, the offender would continue to commit criminal offenses, it being noted this is his sixth and seventh felony. [Appellant, age 22, had five prior felony convictions for burglary, auto theft, auto burglary and second degree forgery.] The Defendant should be punished to deter others from committing crime. He continues to commit crimes even though less restrictive sanctions have been applied. And the isolation of this offender is necessary for the protection of the public among other things.”
After the judgment was entered, appellant was returned to Colorado to finish his prior sentence. His stay in the Fremont County jail was credited against his Colorado term.
INDETERMINATE SENTENCING
Appellant contends that the district court violated § 7-13-201, W.S.1977, which states:
“When a convict is sentenced to the state penitentiary, otherwise than for life, for an offense or crime, the court imposing the sentence shall not fix a definite term of imprisonment, but shall establish a maximum and minimum term for which said convict shall be held in said prison. The maximum term shall not be longer than the longest term fixed by law for the punishment of the offense of which he was convicted, and the minimum term shall not be less than the shortest term fixed by law for the punishment of the offense of which he was convicted.”
According to appellant, the trial court essentially imposed determinate sentences on both counts because there was only a single day between the minimum and maximum sentences. But there is nothing in the statute which requires any fixed period of time between the minimum and maximum, and this court would be interfering with an important legislative function if it undertook to establish such a period. We doubt that the legislature overlooked the obvious possibility that a judge might impose the sentences imposed here. Justice Brown, in a concurring opinion in Jahnke v. State, Wyo., 682 P.2d 991, 1010-1011 (1984), noted that such sentences would be possible under the statute. He stated that the judge in that case “could have sentenced Richard [Jahnke] to not less than nineteen years, eleven months and twenty-nine days.” The legislature has not amended the statute in response to Justice Brown’s observation.
The primary responsibility for criminal sentencing rests with the legislature which has the resources and mandate to create an effective corrections policy. Unless and until the legislature changes § 7-13-201, W.S.1977, sentences like those imposed in *757this case will be considered indeterminate and legal.
TIME SERVED
The district court did not give appellant credit for the time he spent in the Fremont County jail awaiting trial. According to appellant, this decision by the court violates the rule stated in Jones v. State, Wyo., 602 P.2d 378, 381 (1979):
“[A] trial judge has discretion to deny or grant credit for time served in pre-sen-tence custody where: (1) the pre-sen-tence custody is not due to the defendant’s indigency, and (2) the sum of the time spent in pre-sentence custody plus the sentence does not exceed the maximum allowable sentence.” (Emphasis added.)
The problem with this argument is that appellant was not being held in the Fremont County jail solely on the Wyoming charges. He was serving his Colorado sentence and could not have been released on bond by the district court. The Interstate Agreement on Detainers provides:
“(d) The temporary custody referred to in this agreement shall be only for the purpose of permitting prosecution on the charge or charges contained in one (1) or more untried indictments, informations or complaints which form the basis of the detainer or detainers or for prosecution on any other charge or charges arising out of the same transaction. Except for his attendance at court and while being transported to or from any place at which his presence may be required, the prisoner shall be held in a suitable jail or other facility regularly used for persons awaiting prosecution.
“(e) At the earliest practicable time consonant with the purpose of this agreement, the prisoner shall be returned to the sending state.
“(f) During the continuance of temporary custody or while the prisoner is otherwise being made available for trial as required by this agreement, time being served on the sentence shall continue to run but good time shall be earned by the prisoner only if, and to the extent that, the law and practice of the jurisdiction which imposed the sentence may allow.
(g) For all purposes other than that for which temporary custody as provided in this agreement is exercised, the prisoner shall be deemed to remain in the custody of and subject to the jurisdiction of the sending state and any escape from temporary custody may be dealt with in the same manner as an escape from the original place of imprisonment or in any other manner permitted by law.” (Emphsis added.) Section 7-15-101, Art. V, W.S.1977.
If we were to hold as appellant suggests, he would receive credit against both his Colorado and Wyoming sentences for the time spent awaiting trial in Wyoming. He would receive a special benefit because he happened to commit the Wyoming crime while still incarcerated for a prior Colorado offense. Clearly, the Interstate Agreement on Detainers is not intended to reward a criminal for committing his crimes from prison. The district court properly held that appellant was not entitled to credit against his Wyoming sentences for the time spent in the Fremont County jail.
ABUSE OF DISCRETION
In Martin v. State, Wyo., 720 P.2d 894 (1986), we clarified the meaning of the term “abuse of discretion.” We explained that a court can abuse its discretion even if it does not commit an error of law; therefore, the frequently cited statement in Martinez v. State, Wyo., 611 P.2d 831, 838 (1980), that
“[a]n abuse of discretion has been said to mean an error of law committed by the court under the circumstances”
is seriously misleading. When the misleading sentence is stricken from the Martinez definition, the traditional test re-emerges.
“‘A court does not abuse its discretion unless it acts in a manner which exceeds the bounds of reason under the circumstances. In determining whether there has been an abuse of discretion, the ulti*758mate issue is whether or not the court could reasonably conclude as it did.’ ” See Martin v. State, supra, 720 P.2d at 896 (quoting from Martinez v. State, supra, 611 P.2d at 838).
The sentences imposed in this case were well within the bounds of reason under the circumstances. Appellant had committed five prior felonies and was serving time for his most recent crime when he planned the armed robbery of his grandmother. Apparently his prior prison stays had no rehabilitative effect, and the district court correctly concluded that he represented a continuing threat to others. The aggravated robbery and burglary which he planned were serious crimes that involved threatened violence to a particularly vulnerable victim. There were no mitigating factors.
Appellant contends that the district court imposed severe sentences in order to punish the public defender’s office. But the statements he quotes from the record to support his argument indicate nothing of the kind. It is perfectly clear why appellant received the most severe sentences that could have been legally imposed — he earned them. There was no abuse of discretion.
MERGER
At oral argument before this court, appellant contended that he should have been sentenced under only one of the charges because of the doctrine of merger. This issue was not raised in the district court or mentioned in appellant’s brief to this court.
“Except for appeals which involve issues of jurisdiction or fundamental rights, we will not ordinarily consider contentions of error unless the trial court has first been apprised thereof and given an opportunity to rule upon the alleged error.” Dennis v. Dennis, Wyo., 675 P.2d 265, 266 (1984).
“[Ujnder the settled authority of this court we will not consider [those] points which have not been briefed * * Za-netti v. Zanetti, Wyo., 689 P.2d 1116, 1123 (1984).
“We are, however, under an independent duty to examine whether this court’s jurisdiction has been properly invoked, even where the parties have not raised the jurisdictional issue.” Kurpjuweit v. Northwestern Development Company, Inc., Wyo., 708 P.2d 39, 44 (1985).
Although appellant failed to preserve the issue in either the district court or this court, we could theoretically conduct our own investigation to determine whether the district court had jurisdiction to sentence appellant under both counts.
“[I]f the appellate court notices that the sentence is illegal it can, on appeal from the conviction, order the trial court to reduce the sentence to the maximum that would be valid.” See 3 Wright, Federal Practice and Procedure: Criminal 2d § 588, at 415 (1982).
In this case, however, we are not confronted with an obviously illegal sentence which we can simply correct. Appellant’s merger argument is complex and would have to be researched extensively. This is exactly the kind of issue that defense counsel should bring to the attention of the trial court and the State at the proper times so that it can be thoroughly explored and argued and fairly adjudicated. Instead of conducting our own investigation of the merger issue, we will invoke the
“general rule that a motion for correction [of sentence] under Rule 36 [W.R. Cr.P.] should be made to the sentencing court in the first instance.” Price v. State, Wyo., 716 P.2d 324, 328 (1986).
If appellant makes a proper motion to correct this claimed illegal sentence under Rule 36, W.R.Cr.P., and if the motion is denied, then the issue might more properly be brought before this court on appeal.
JUDICIAL INTERVENTION
We do not dispute the proposition that a sentence which gives the same minimum and maximum sentences (i.e., three years to three years) is in fact a determinate sentence and illegal under an indeter-*759mínate sentencing scheme. The decided cases generally stand for this proposition. Just two states — New Mexico and Tennessee — have held that a sentence with the identical minimum and maximum terms is indeterminate. The New Mexico legislature has since adopted a determinate sentencing structure; the Tennessee legislature has since adopted legislation specifying the required range between the minimum and maximum sentences. The question we confront here is whether a difference of one day, which technically satisfies the statutory requirement of minimum and maximum sentences, so violates the spirit of the indeterminate sentencing scheme that this court should act in the face of legislative silence concerning a mandatory spread between minimum and maximum sentences. We do learn from New Mexico and Tennessee in that we will leave this matter to the legislature as was done in those states. We do not say a day is the same as one year, two years, or five years. There are different ranges between sentences, and we say only that where the maximum sentence is greater than the minimum, it is technically an indeterminate sentence. We will discuss the cases cited by the dissent which are said to be authority for judicially creating the spread between minimum and maximum sentences.
In several states, appellate courts are given specific authority to reduce sentences on appeal. Wyoming statutes contain no such grant of authority. The Illinois Supreme Court, under such authority, has held that a sentence, while complying with the letter of the indeterminate sentencing legislation, might so violate its spirit as to justify a different sentence, but continuing implied that, with appropriate justification from the sentencing judge, a sentence whose minimum and maximum terms are separated by one day might be upheld. People v. Harper, 50 Ill.2d 296, 278 N.E.2d 771, 774 (1972).
In People v. Scott, 117 Ill.App.2d 344, 253 N.E.2d 553 (1969), the appellant sought reduction of an excessive sentence, 7-14 years for armed robbery. At that time, as when Harper, supra, was decided, a statute which specifically authorized reduction of sentences by the reviewing court was in effect. Under such authority, and because the appellant had no “prior criminal propensities,” the court reduced the minimum sentence to five years.
In People v. Pacheco, 41 Colo.App. 188, 581 P.2d 741 (1978), the defendant appealed his sentence of 34-38 years for assault in the first degree as being excessive. A statute authorized appellate review of sentences. The court, after alluding to the fact that this was a maximum sentence, held the sentence justified under the circumstances and affirmed.
Courts have tinkered with sentences to make them comply with indeterminate sentencing statutes. Thus, after upsetting defendant’s sentence of death, the court discussed the judicial power to punish for not less than 20 years. The court explained that where only a minimum term is specified by statute, the court must set a maximum, up to life, to allow the possibility of parole and ordered a sentence of 20 years to life, the full statutory range. Spillers v. State, 84 Nev. 23, 436 P.2d 18, 22-23 (1968), overruled on other grounds, Bean v. State, 86 Nev. 80, 465 P.2d 133 (1970). There was no discussion concerning a minimum spread that would allow for the possibility of parole.
In Ard v. State ex rel. Superior Court of Pima County, 102 Ariz. 221, 427 P.2d 913 (1967), the trial court, under a statute providing for a 10 year sentence, imposed a life sentence. The Arizona Supreme Court set aside the determinate life sentence as violative of the indeterminate sentencing statute. Where a statute specifies only a minimum term, the court may not impose a maximum determinate sentence. Id., 427 P.2d at 916.
In In re Shequin, 131 Vt. 111, 300 A.2d 536 (1973), the court found a sentence of 35-40 years for second degree murder not to violate the spirit and intent of the indeterminate sentencing statute. In Woodmansee v. Stoneman, 133 Vt. 449, 344 A.2d 26, 33 (1975), the court likewise ap*760proved a sentence of 6-7 years. And In re Parent, 125 Vt. 475, 218 A.2d 717 (1965), held improper a sentence with identical minimum and maximum terms.
Just one court, Michigan, has, without statutory authority, created the range to be imposed between the minimum and maximum terms. The Michigan court first refused to hold sentences whose minimum and maximum terms were separated by one day to be determinate sentences. People v. Lessard, 22 Mich.App. 342, 177 N.W.2d 208 (1970). Later the court reversed itself and overturned sentences with 30 days between the minimum and maximum, observing that although this was technically an indeterminate sentence, it failed “to comply with the clear intent and purpose of the indeterminate sentence act,” and held “that any sentence which provides for a minimum exceeding two-thirds of the maximum is improper as failing to comply with the indeterminate sentence act.” People v. Tanner, 387 Mich. 683, 199 N.W.2d 202, 204-205 (1972). Under this judicially promulgated law governing sentences, the court of appeals reduced a 35-50 year sentence to 33V2-50 years, People v. Duffy, 67 Mich. App. 266, 240 N.W.2d 771, 773 (1976), and a 23-24 month sentence to 16-24 months, People v. Redwine, 73 Mich.App. 83, 250 N.W.2d 550, 551 (1976). Sentences to be imposed for violation of numerous criminal statutes is a matter ordinarily better left to the legislature. This court, therefore, declines the invitation to engage in judicial legislation by adopting an appropriate spread between minimum and maximum sentences. We perceive that if a spread between minimum and maximum sentences is appropriate, that is a simple matter for the legislature to provide.
LEGISLATIVE INTENT
The recital of legislative history is impressive, but it underscores the wisdom of the rule stated in Independent Producers Marketing Corporation v. Cobb, Wyo., 721 P.2d 1106, 1108 (1986), that affidavits by “persons involved in the enactment of a statute are not a proper source of legislative history.” Among other factors, we must consider the impact of Daniel v. State, Wyo., 644 P.2d 172 (1982), and similar cases concerning sentencing. In Daniel v. State, this court upheld a sentence of 19-20 years imprisonment on a conviction of involuntary manslaughter, where 20 years was the maximum allowed. We noted in Daniel that the trial judge is given wide discretion in sentencing. Id., quoting Jones v. State, Wyo., 602 P.2d 378, 380 (1979). We said:
“Wyoming has a system of indeterminate sentencing, which carries with it an implicit adoption of the philosophy of individual sentencing. This system of indeterminate sentencing necessitates the granting of broad discretion to the trial judge, who must choose from the sentencing alternatives and the range of permissible penalties.” (Footnote omitted.) 644 P.2d at 178.
We rejected the notion that uniformity in sentencing is required because crimes and criminals vary:
“The circumstances of each crime are different. The background of each convicted person is different and his rehabilitative needs are different. Also, the potential of each convict to be a productive member of society is different.” Id., 644 P.2d at 180.
Under the version of § 7-13-402(a), W.S. 1977, then in effect, Daniel would not have been eligible for parole for 19 years. The perceived injustice of the sentence was heightened by the fact that had Daniel been convicted of first degree murder with which he was originally charged (644 P.2d at 173, n. 1) and sentenced to life, he would, in all likelihood, have been released well before 19 years.
In responding to the perceived inequities of discretionary indeterminate sentencing, the legislature did not impose determinate sentencing nor even specify a mandatory period between minimum and maximum sentences. Rather, less than two years after Daniel was decided, the legislature made only two changes: § 7-13-402(a) was amended to provide that inmates were eligi*761ble for parole after serving the minimum sentence less good time. Section 7-13-423 was added, authorizing rules for good time to be deducted from either the maximum or minimum sentence or both. The rules provide for up to 15 days per month, after the first six months, good time off the minimum sentence. In all events, good time is a matter of grace and not of right.
Thus, although the legislature perceived the potential difficulties of combining indeterminate sentencing and judicial discretion, it chose only these less restrictive means to remedy the situation. Emphatically it did not mandate a spread of years or days between the minimum and maximum sentences. Someday it may choose to do so. Until then this court must apply the sentencing statutes as they are written.
Affirmed.
THOMAS, C.J., concurs in result only.
URBIGKIT and MACY, JJ., each filed separate dissenting opinions.