When an existing or future contract expires, the Board may, with the publisher’s approval, continue the contract for any particular book or books for a period not less than one or more than five years. If a publisher desires to terminate a contract that has been extended beyond the original contract period, he shall give notice to the Board 90 days prior to May 1. The Board may then proceed to a new adoption. (1955, c. 1372, art. 24, s. 7; 1969, c. 519, s. 1; 1981, c. 423, s. 1.)