In Randazzo v. Kroenke, 373 Mich 61, 67; 127 NW2d 880 (1964), the Supreme Court of Michigan stated: "Separate writings which are related in subject matter may be read together to satisfy the requirement of the statute for a memorandum not only where both are signed by the party to be charged, but also where only one of them is signed, if they are so connected that the signature appearing upon the one can be said to authenticate the other one which is unsigned. Under such circumstances it is deemed that there is in fact a reference in the one instrument to the other, or, as some authorities declare, the reference required to incorporate the other paper in the memorandum is implied, or, as otherwise stated, there is an incorporation by necessary inference." Quoting 49 Am Jur, Statute of Frauds, 394, p 699.