Shiva Purana
तत्पुत्रास्तादृशाश्चासंश्चत्वारो मुनिसत्तमाः ॥ शिवपूजारता नित्यं पित्रोरनवमास्सदा ॥ ९ ॥
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