Udyoga Parva, Adhyāya 101: Bhogavatī-varṇana, Nāga-vaṃśa-kathana, and Sumukha-vivāha-prastāva
फेनपा नाम ते ख्याता: फेनाहाराश्न मातले । उग्रे तपसि वर्तन्ते येषां बिभ्यति देवता:,मातले! फेनका आहार करनेके कारण वे महर्षिगण “फेनप” नामसे विख्यात हैं। वे बड़ी कठोर तपस्यामें संलग्न रहते हैं। उनसे देवतालोग भी डरते हैं
phenapā nāma te khyātāḥ phenāhārāśn māṭale | ugre tapasi vartante yeṣāṃ bibhyati devatāḥ ||
O Mātali, those sages are renowned by the name Phenapā, for they subsist on foam as their food. They abide in exceedingly austere tapas; such is the intensity of their discipline that even the gods stand in awe of them.
नारद उवाच