Shiva Purana
तत्रापि शयनस्थानं कुर्यान्मंडलमध्यतः ॥ शुद्धैर्जलैः स्नापयित्वा लिंगमभ्यर्चयेत्क्रमात् ॥ १६ ॥
A resting place shall be made in the middle of the Maṇḍala. After bathing the liṅga with pure water he shall worship it.
english translation
tatrApi zayanasthAnaM kuryAnmaMDalamadhyataH ॥ zuddhairjalaiH snApayitvA liMgamabhyarcayetkramAt ॥ 16 ॥
hk transliteration by Sanscript