(a) Every licensed dealer shall keep and maintain for a period of four years such records in such form as the department shall by regulation prescribe. The records shall be maintained at the location for which the license is issued.

(b) A contract of sale complying with the provisions of this article shall be signed by the parties to a sale of cigarettes and shall be kept on file by each party at the location for which the license is issued. In the case of a dealer having more than one location under common ownership, the contract of sale shall be kept at the business or corporate headquarters. A contract of sale shall include, but not be limited to, an actual document or Internet or electronic evidence indicating that a transaction for the sale of cigarettes has taken place.