Shiva Purana
ब्राह्मणः क्षत्रियो वैश्यः शूद्रो वा प्रतिलोमजः । पूजयेत्सततं लिंगं तत्तन्मंत्रेण सादरम् ३९ ।
Brahmins, Kṣatriyas, Vaiśyas, Śūdras, persons born of inter-caste marriages and others shall worship the phallic icon with great devotion with the respective mantras.
english translation
brAhmaNaH kSatriyo vaizyaH zUdro vA pratilomajaH । pUjayetsatataM liMgaM tattanmaMtreNa sAdaram 39 ।
hk transliteration by Sanscript