Shiva Purana
कुर्यात्स्त्रिसन्ध्यमप्येवमेतत्पाशुपतं व्रतम् ॥ भुक्तिमुक्तिप्रदं चैतत्पशुत्वं विनिवर्तयेत् ॥ २६ ॥
He shall act thus during all the three Sandhyās. This Pāśupata Vrata yields worldly pleasures and salvation dispelling Paśu-hood.
english translation
kuryAtstrisandhyamapyevametatpAzupataM vratam ॥ bhuktimuktipradaM caitatpazutvaM vinivartayet ॥ 26 ॥
hk transliteration by Sanscript