Agniveshyagrihyasutra 3.3.1.2

3.3.1.2

pūrvedyuḥ sāyamaupāsanaṃ hutvā prāṇāsāyamya saṃkalpya śvaḥ pitṛbhyo māsiśrāddhaṃ kariṣya iti vā śvo yajñaśarmaṇaḥ nakṣatraśrāddhaṃ kariṣya iti vā śvo yajñaśarmaṇaḥ tripakṣaśrāddhaṃ kariṣya iti vā śvo yajñaśarmaṇaḥ ṣaṇmāsaśrāddhaṃ kariṣya iti vā śvo yajñaśarmaṇaḥ saṃvatsaraśrāddhaṃ kariṣya iti vā śvo yajñaśarmaṇaḥ sapiṇḍīkaraṇaśrāddhaṃ kariṣya iti vā saṃkalpya brāhmaṇān śucīn śrotriyān daridrān vedajñān samāṅgān agotrānasamānārṣeyān kṣaṇaṃ karoti \

On the previous day, having offered the evening aupāsana oblation, having controlled the breath, having formed the intention: "Tomorrow I shall perform the monthly śrāddha for the ancestors," or "Tomorrow I shall perform the asterism śrāddha of Yajñaśarman," or "Tomorrow I shall perform the three-fortnight śrāddha of Yajñaśarman," or "Tomorrow I shall perform the six-month śrāddha of Yajñaśarman," or "Tomorrow I shall perform the one-year śrāddha of Yajñaśarman," or having formed the intention: "Tomorrow I shall perform the sapiṇḍīkaraṇa śrāddha of Yajñaśarman"—one invites Brahmins who are pure, learned in the Veda, poor, knowers of the Veda, with sound limbs, not of the same gotra, and not of the same ancestral rishis.