Garudapurana 3.29.55

3.29.55

trivāratīrthagrahaṇasya kāle kṛṣṇaṃ rāmaṃ vyāsadevaṃ krameṇa /
śaṅkhodakasyoddharaṇe caiva kāle mukundarūpaṃ saṃsmaretsarvadaiva //

At the time of taking the holy water three times, [one should remember] Kṛṣṇa, Rāma, and the divine Vyāsa in sequence; / and when taking water from the conch, one should always remember the form of Mukunda.