Shiva Purana
सर्वमेतत्परित्यज्य कर्मजालमशेषतः । भक्त्या परमया विद्वाँ ल्लिंगमेकं प्रपूजयेत् ३३ ।
All other rites can entirely be abandoned. A really learned man shall worship only the phallic image with great devotion.
english translation
sarvametatparityajya karmajAlamazeSataH । bhaktyA paramayA vidvA~ lliMgamekaM prapUjayet 33 ।
hk transliteration by Sanscript