Garudapurana 1.34.5

1.34.5

asyāṅgāni mahādeva tāñchṛṇuṣva vṛṣadhvaja /
oṃ kṣāṃ hṛdayāya namaḥ /
oṃ kṣīṃ śirase svāhāśiraḥ proktaṃ kṣūṃ vaṣaṭ tathā //

Hear its limb-[mantras], O Mahādeva, O you whose banner bears a bull: / ‘Oṃ kṣāṃ to the heart, namaḥ’; / ‘Oṃ kṣīṃ to the head, svāhā’—the head is proclaimed; and likewise ‘kṣūṃ vaṣaṭ’;