Shiva Purana
तस्मात्सर्वप्रयत्नेन सेव्यते काशिका पुरी ॥ अव्यक्तलिंगं मुनिभिर्ध्यायते च सदाशिवः ॥ २६ ॥
Hence the people resort to Kāśī with every strenuous effort. The sages meditate on Sadāśiva in the form of his phallic image.
english translation
tasmAtsarvaprayatnena sevyate kAzikA purI ॥ avyaktaliMgaM munibhirdhyAyate ca sadAzivaH ॥ 26 ॥
hk transliteration by Sanscript