The principal question presented upon this appeal is: may an issue which has been discussed in pre-contract negotiations and rejected by one of the negotiating parties, thus preventing its inclusion in the master contract, be later raised in judicial proceedings? We conclude that, ordinarily, it may not. We further conclude that mandamus is not available under the circumstances of this case. The judgment is affirmed.
The appellants in this case (hereinafter referred to as Webster) are individual teachers employed by the Bismarck Public School District (School District) to teach at Bismarck Junior College. These teachers were employed for the nine-month school year. It has been the custom in the past to pay teachers with a nine-month contract on a twelve-month basis. In the spring of 1980, negotiations were initiated to draw up an employment contract between the teachers and the School District for fiscal year 1980-81. During these negotiations, the teachers were represented by Professional Negotiations Association (PNA). One of the issues PNA presented to the School District was the desire of some teachers employed on a nine-month contract to have the option to be paid on a nine-month basis. The School District refused to concede on *99this issue, however, and, after lengthy discussion, the matter was dropped.
Later that summer, a federal mediator requested both parties to disclose remaining issues to be negotiated. The “option” question was not one of those submitted to the mediator. The master contract between the two negotiating parties was subsequently executed on September 9, 1980. It did not prescribe any particular schedule of payments.
Although some of the teachers objected to the absence of a provision in the master contract allowing them the option of being paid on a nine-month schedule, the master contract was, nevertheless, approved by the teachers. The individual contracts sent to the teachers, however, included a provision that their salary payments would extend over a twelve-month period.
This mandamus suit was then brought by the individual teachers to require the School District to pay their salaries concurrently with their period of employment.
The district court held that because the matter had been brought up in pre-contract negotiations it could not again be brought up as a subject of litigation by individual members of the bargaining unit. The teachers’ complaint was then dismissed with prejudice.1
The federal labor relations laws do not apply to public employees and, therefore, the issue to be resolved in this case is a question of state law. Chapter 15-38.1, NDCC, sets out the procedures for collective bargaining between teachers and school boards. See Fargo Ed. Ass’n v. Paulsen, 239 N.W.2d 842 (N.D.1976).
In this instance, Webster objected to the absence of a provision allowing teachers the option to be paid concurrently with their period of employment. Section 15-38.1-08, NDCC. Nevertheless, the master contract was ratified by a majority of the members in their appropriate negotiating unit.
Webster argues that because the master contract did not refer to any time schedule for payments, then common law and §§ 34^14-02 and 34-14-04.1, NDCC, require teachers employed on a nine-month contract to be paid on a nine-month basis', unless they otherwise agree. These statutes, however, are not clearly applicable. No common law right has been identified as applicable.
Although the master contract did not mention a schedule for outlay of payments, it was not, under the circumstances, improper for the School Board to adhere to past custom and practice.
“... the labor contract — burdened with the task of regulating a complex work community on a continuing basis — cannot reduce to writing each and every norm or rule that has been developed over time to govern the parties’ activities. It is common to treat the collective bargaining agreement as comprised not only of the written and executed document but also of plant customs and industrial practices as well as of informal agreements and concessions made at the bargaining table but not reduced to writing.” R. Gorman, Basic Text On Labor Law, at 541 (1976).
After a party attempts but fails in contract negotiations to obtain a specific provision in an agreement, in order to show entitlement to a writ of mandamus from the courts it must be shown that there is a clear legal right to that which is sought. Fargo Ed. Ass’n v. Paulsen, supra; Fargo Ed. Ass’n v. Fargo Public Sch. Dist., 291 N.W.2d 267 (N.D.1980); and §§ 32-34-01 and 32-34-02, NDCC. No such clear legal right has been shown.
The judgment is affirmed.
ERICKSTAD, C.J., and PAULSON, SAND and VANDE WALLE, JJ., concur.. This matter was before the district court on two separate occasions. The court held the first proceedings in abeyance while the teachers exhausted all possible administrative remedies. When the issue could not be resolved administratively, then it was brought once again before the court.