Shiva Purana
देवा अपि पितॄन्स्वर्गे यजंत इति मे श्रुतम् ॥ एतदिच्छाम्यहं श्रोतुं विस्तरेण ब्रवीहि मे ॥ १८॥
I have heard that even the gods worship the manes. I wish to hear this. Please mention this in detail.
english translation
devA api pitRRnsvarge yajaMta iti me zrutam ॥ etadicchAmyahaM zrotuM vistareNa bravIhi me ॥ 18॥
hk transliteration by Sanscript