Shiva Purana

siva.sh/siva-purana/kotirudra-samhita/16/9

तत्पुत्रास्तादृशाश्चासंश्चत्वारो मुनिसत्तमाः ।। शिवपूजारता नित्यं पित्रोरनवमास्सदा ।। ९ ।।

sanskrit

O excellent sages, he had four sons like him. They were not inferior to their parents and they were ever engaged in the worship of Śiva.

english translation

tatputrAstAdRzAzcAsaMzcatvAro munisattamAH || zivapUjAratA nityaM pitroranavamAssadA || 9 ||

hk transliteration by Sanscript