四分律比丘含注戒本 1.326

1.326

有住信憂婆私於二法中以一一法說，若僧伽婆尸沙，若波逸提；是坐比丘自言「我犯是事」，於二法中應一一治，若僧伽婆尸沙，若波逸提，如住信憂婆私所說，應如法治是比丘，是名不定法。

'and a trustworthy upāsikā alleges one of the two dharmas—either a saṃghāvaśeṣa or a prāyaścittika; and if the seated bhikṣu himself admits, "I committed this matter," he should be dealt with according to that one of the two dharmas—either a saṃghāvaśeṣa or a prāyaścittika—as stated by the trustworthy upāsikā, this bhikṣu should be dealt with according to the Dharma. This is called an aniyata dharma.'