四分律行事鈔資持記 3.710

3.710

三中。引佛真規，以為後則。文列三相，隨一即成。儼頭，《經音義》云：字合作頷，世謂點頭是也。

In the third [heading], the Buddha's genuine standard is cited to serve as a rule for later generations. The text lists three signs; meeting any single one completes the agreement. For 'nodding the head' (儼頭), the Jingyin yi says: the character should properly be written '頷' (nod); what the world calls nodding the head is this.