Shiva Purana
प्रणवस्य ऋषिर्ब्रह्मा देवि गायत्रमीरितम् ॥ छन्दोत्र देवताहं वै परमात्मा सदाशिवः ॥ ६१ ॥
O goddess, the sage of Praṇava is Brahmā, the metre is Gāyatrī and the deity is the great Ātman, Sadāśiva that is I myself.
english translation
praNavasya RSirbrahmA devi gAyatramIritam ॥ chandotra devatAhaM vai paramAtmA sadAzivaH ॥ 61 ॥
hk transliteration by Sanscript