Shiva Purana
तत्रापि मम ते पुत्रा भविष्यन्ति सुयोगिनः ॥ प्लक्षो दार्भायणिश्चैव केतुमान् गौतमस्तथा ॥ २९ ॥
There too, experts in Yoga, will be my sons viz. Plakṣa, Dārbhāyaṇi, Ketumān and Gautama.
english translation
tatrApi mama te putrA bhaviSyanti suyoginaH ॥ plakSo dArbhAyaNizcaiva ketumAn gautamastathA ॥ 29 ॥
hk transliteration by Sanscript