Skandapurana 6.3.20.57

6.3.20.57

śrāddhaṃ śrāvaṇyāmāgrayaṇaṃ ca caitrāśvayujyāṃ daśapaurṇamāsyām .
nirūḍhapaśusavanasautrāmaṇyagniṣṭomātyagniṣṭomāḥ .. 20.57 ..

the ancestral rite on the full-moon day of Śrāvaṇa, the first-fruits sacrifice on the full-moon of Caitra and Āśvina, the animal sacrifice, the sautrāmaṇī, the agniṣṭoma, the atyagniṣṭoma;