Garudapurana 1.23.16

1.23.16

ātmānaṃ padmasaṃsthaṃ ca hauṃ śivāya tato bahiḥ /
dvāre nandimahākālau gaṅgā ca yamunātha gauḥ //

[Visualising] oneself seated on a lotus and [saying] "Hauṃ to Śiva," then outside, / at the door, Nandi and Mahākāla, Gaṅgā and Yamunā, and the cow;