Shiva Purana
यथा नदीषु सर्वासु ज्येष्ठा श्रेष्ठा सुरापगा । तथा सर्वेषु लिंगेषु पार्थिवं श्रेष्ठमुच्यते 1-19-१० ।
Just as the celestial river Gaṅgā is the oldest and the most excellent of all rivers, so also is the earthen phallic image of Śiva the most excellent of all.
english translation
yathA nadISu sarvAsu jyeSThA zreSThA surApagA । tathA sarveSu liMgeSu pArthivaM zreSThamucyate 1-19-10 ।
hk transliteration by Sanscript