Garudapurana 1.219.4

1.219.4

tataḥ amukavṛddhau amukagotrāyā matprapitāmahyā amukadevyā nāndīmukhyāḥ śrāddhaṃ siddhānnena yuṣmāsu mayā kartavyamiti prapitāmahībrāhmaṇāmantraṇam /
kariṣyāmīti tenokte itthameva pramātāmahyādibrāhmāṇamantraṇam //

Then: "On this auspicious occasion, for my great-grandmother of such-and-such gotra, such-and-such name, of the Nāndīmukha class, I shall perform the śrāddha with cooked food among you"—this is the invitation to the brāhmaṇa representing the great-grandmother. / When he has said, "I will perform it," exactly in this manner is the invitation to the brāhmaṇas representing the maternal great-grandmothers and the others.