Okla. Stat. tit. 12A, § 12A-2A-204: Formation in general

FORMATION IN GENERAL

(1) A lease contract may be made in any manner sufficient to

show agreement, including conduct by both parties which recognizes

the existence of a lease contract.

(2) An agreement sufficient to constitute a lease contract may

be found although the moment of its making is undetermined.

(3) Although one or more terms are left open, a lease contract

does not fail for indefiniteness if the parties have intended to

make a lease contract and there is a reasonably certain basis for

giving an appropriate remedy.