Skandapurana 5.113.13

5.113.13

sa kadācidyayau vipro nāgatīrthaṃ prati dvijāḥ ..
śrāvaṇasyāsite pakṣe paṃcamyāṃ paryaṭanvane ..13..

Once, O twice-born ones, that brahmin went toward Nāgatīrtha / on the fifth day in the dark half of Śrāvaṇa, wandering in the forest. / 13