A. Under the Convention, a valid contract need not be in writing. Purchase goods, supplies, equipment or services under this Contract.Business expenses as outlined in the. Cook Global Travel and Expense Policy. Fourthly, the CISGS is supposed to over- come the inadequacies of the CISG's approach to contract formation and the obligations of the parties (5.4). A contract of sale of goods is where the seller agrees to transfer the property in goods to a buyer for the price. Said goods must be as discussed and agreed. Taking into account the role that African countries have played in the United Nations Commission on International Trade.