Shiva Purana
अस्याः परमविद्यायास्स्वरूपमधुनोच्यते ॥ आदौ नमः प्रयोक्तव्यं शिवाय तु ततः परम् ॥ ३८ ॥
Now I mention the form of this great mantra. The word ‘Namaḥ’ shall be uttered at first. It shall be followed by the word ‘Śivāya’.
english translation
asyAH paramavidyAyAssvarUpamadhunocyate ॥ Adau namaH prayoktavyaM zivAya tu tataH param ॥ 38 ॥
hk transliteration by Sanscript