Morgan Truck Body v. Integrated Logistics Solutions - ED Pa. - March 20, 2008
http://www.paed.uscourts.gov/documents/opinions/08D0320P.pdf
Under Pennsylvania law, “an implied-in-fact contract is a true contract arising from mutual agreement and intent to promise, but where the agreement and promise have not been verbally expressed. The agreement is inferred from the conduct of the parties."
"Contracts are often spoken of as express or implied. The distinction involves, however, no difference in legal effect, but lies merely in the mode of manifesting assent. Just as assent may be manifested by words or other conduct, sometimes including silence, so intention to make a promise may be manifested in language or by implication from other circumstances, including course of dealing or usage of trade or course of performance. Restatement (Second) of Contracts § 4 cmt. a; see also Rissi v. Cappella, 918 A.2d 131, 140 (Pa. Super. 2007)
"When parties continue to conduct business following the expiration of their written agreement, the law may recognize their relationship as an 'implied-in-fact' contract."