Including Gd's Name: Rosh HaShanah 18b
Including the statement of transfer, as the minimal requirement: Kiddushin 26a
The Time
The time on the Bill is the time at which it is meant to be activated [Zemano Mochi'ach Alav]: Ketuvot 2b
One can't collect on a Bill without the time being written on it: Bava Metzia 7b
Validity of a bill with an early time listed for the deal mentioned: Rosh HaShanah 2a, 8a; Bava Metzia 17a, 72a
Validity of a bill with a late time listed for the deal mentioned: Rosh HaShanah 2a, 8a
A Bill which is written during the day and signed at night: Gittin 17a
Numbering of Years on a Bill
The 1st of Nisan is the beginning of year in numbering the years of a Jewish King on a legal document: Rosh HaShanah 2a, 2a-3a, 8b
The 1st of Tishrei is the beginning of year in numbering the years of a non-Jewish King on a legal document: Rosh HaShanah 2a, 2a-4a, 8b
Considering the first/last day of the year to be the entire year, in calculating a king's reign: Rosh HaShanah 2b, 7b
Counting a year for two different kings, who ruled during that year: Rosh HaShanah 2b
The amount of money involved
Where the Species of coin is mentioned in plural, but without a number: Bava Metzia 4b
If one left out a condition allowing collection of properties which become bound to other individuals after this Bill is written: Bava Metzia 14a, 15b
The above, for a Bill of Lending or for a Bill of Sale: Bava Metzia 14a, 15b
Whether a scribe must ask before writing a condition allowing collection of bound-properties & the value of improvements made to the property from the finest property automatically: Bava Metzia 14a, 15a
Other Issues
Including a condition which is against Torah law (Matneh Al Mah sheKatuv baTorah): Makkot 3b
The Bill may be written in any language: Gittin 19b
The Bill must be written with a writing which is in-alterable without being noticed: Gittin 11a, 19b, 20b, 21b
The Bill must repeat the essence of its point in the last line [preventing addition to it]: Gittin 11a, 19b
Writing a bill on erased paper: Gittin 22b
