Maryland Code, Commercial Law § 22-210

(a) Except as otherwise provided in subsection (b) of this section and subject to § 22-301 of this title, if a contract is formed by conduct of the parties, the terms of the contract are determined by consideration of the terms and conditions to which the parties expressly agreed, course of performance, course of dealing, usage of trade, the nature of the parties' conduct, the records exchanged, the information or informational rights involved, and all other relevant circumstances. If a court cannot determine the terms of the contract from the foregoing factors, the supplementary principles of this title apply.

(b) This section does not apply if the parties authenticate a record of the contract or a party agrees, such as by manifesting assent, to the record containing the terms of the other party.