The distinction between an implied contract (implied in fact) and a quasi contract (implied in law) was presented in a somewhat unusual fashion in the federal case of Holbert v. United States decided by the District Court for the Eastern District of Tennessee. Whether or not a federal district court had jurisdiction over plaintiff's case turned on whether the claim was based on implied contract or on quasi contract.
One of the grounds on which the Tucker Act confers jurisdiction on federal district courts to entertain actions against the United States is where the claim is based "upon any express or implied contract with the United States." The Holbert court was of the opinion that this provision of the Tucker Act gives jurisdiction over implied contract only and that the act does not extend that jurisdiction to actions sounding in quasi contract. In determining whether the federal district court had jurisdiction over plaintiff's claim, the pivotal point thus was whether plaintiff's claim was bottomed on implied contract or quasi contract.
Paul J. Hartman,
Contracts -- 1959 Tennessee Survey,
12 Vanderbilt Law Review
Available at: https://scholarship.law.vanderbilt.edu/vlr/vol12/iss4/10