四分律行事鈔資持記 3.16

3.16

三約條分。非出本律；世中相傳，故云律無等。十九十七，趣舉中品，如後細分。

Third, dividing according to the strips: This does not come from our own vinaya; it has been passed down in the world, hence [the text] says "the vinaya does not have..." and so on. Nineteen and seventeen merely cite the middle grade, as will be divided in detail below.