(Mishnah): In a get pashut (a regular document), the witnesses are signed inside. In a get mekushar (a tied document), the witnesses are signed on the back. If a get pashut had its witnesses signed on the back, or if a get mekushar had its witnesses inside it, they are both pasul.

R. Chananya ben Gamliel: If a get mekushar had its witnesses signed inside it, it is valid, as it can become a get pashut.

Rabban Shimon ben Gamliel: Everything follows the local custom.

(Gemara) - question: Where in Tanach is there a reference to a get mekushar?

Answer (R. Imi): The pasuk states (Yirmiyahu 32:11), "And I took the deed of the purchase, that which was signed'' - this refers to a get mekushar; "and that which was open'' -this refers to the regular part of a get mekushar; "according to the law and the conditions'' - the differences between these two types of documents - a get pashut has two witnesses and a get mekushar has three; a get pashut has witnesses signed inside it and a get mekushar has witnesses signed on the back.

Answer #2 (Rabbanan of Kisarin): "And I took the deed of the purchase'' - this refers to a get pashut; "that which was signed'' - this refers to a get mekushar; "and that which was open'' - this refers to the regular part of a get mekushar; "according to the law and the conditions'' - the differences between these two types of documents - a get pashut has two witnesses and a get mekushar has three; a get pashut has witnesses signed inside it and a get mekushar has witnesses signed on the back.