Shiva Purana
तस्माज्जन्मनिवृत्त्यर्थं शिवलिंगं प्रपूजयेत् । माता देवी बिंदुरूपा नादरूपः शिवः पिता ९१ ।
Hence to ward off future births, the devotee shall worship the phallic emblem of Śiva. Goddess of the form of Bindu is the mother and Śiva of the form of Nāda is the father.
english translation
tasmAjjanmanivRttyarthaM zivaliMgaM prapUjayet । mAtA devI biMdurUpA nAdarUpaH zivaH pitA 91 ।
hk transliteration by Sanscript