An offer or an acceptance need not be evidenced by writing and shall not be subject to any other requirement as to form. In particular, they may be proved by means of witnesses.

1. The communication which one person addresses to one or more specific persons with the object of concluding a contract of sale shall not constitute an offer unless it is sufficiently definite to permit the conclusion of the contract by acceptance and indicates the intention of the offeror to be bound.

2. This communication may be interpreted by reference to and supplemented by the preliminary negotiations, any practices which the parties have established between themselves, usage and the provisions of the Uniform Law on the International Sale of Goods.