四分律行事鈔資持記 3.1130

3.1130

第四門。《四分》三品，七日、半月、一月，倍增。如上，指〈安居篇〉。

The fourth gate: the Dharmaguptaka has three grades—seven days, half a month, and one month, doubling consecutively. "As above" refers to the "Chapter on Vassa".