Shiva Purana
नन्दीश्वर उवाच ॥ इत्युक्त्वा च स्वयं शम्भुर्लिङ्गरूपोऽभवत्तदा ॥ तस्मान्न चलितो धर्मादचलेश इति स्मृतः ॥ ३२ ॥
Nandīśvara said:— After saying this, Śiva assumed the form of phallic image. He became stationary. He is thereafter remembered as Acaleśa.
english translation
nandIzvara uvAca ॥ ityuktvA ca svayaM zambhurliGgarUpo'bhavattadA ॥ tasmAnna calito dharmAdacaleza iti smRtaH ॥ 32 ॥
hk transliteration by Sanscript