Shiva Purana
गुरुदत्तेन मंत्रेण पूजयेद्वृषभध्जम्॥ अन्यथा नाममंत्रेण पूजयेद्वै सदाशिवम् ॥ ५१॥
He shall worship the bull-bannered deity by reciting the mantra imparted by the preceptor. Or he shall worship Sadāśiva by means of Nāmamantras.
english translation
gurudattena maMtreNa pUjayedvRSabhadhjam॥ anyathA nAmamaMtreNa pUjayedvai sadAzivam ॥ 51॥
hk transliteration by Sanscript