Vaishnava Dharmashastra 90.13

90.13

śrāvaṇyāṃ śravaṇayuktāyāṃ jaladhenuṃ sānnāṃ vāsoyugāc chāditāṃ dattvā svargam āpnoti ||

If on the full moon day of the month Srâvana the moon is seen in conjunction with the lunar asterism Sravana and he gives a milch cow covered with two garments, together with food (to a Brâhmana), he attains heaven.