Manusmriti
क्षत्तुर्जातस्तथोग्रायां श्वपाक इति कीर्त्यते । वैदेहकेन त्वम्बष्ठ्यामुत्पन्नो वेण उच्यते ॥ १९ ॥
Moreover, the son of by Kshattri by an Ugra female is called a Svapaka; but one begotten by a Vaidehaka on an Ambashtha female is named a Vena.
english translation
kSatturjAtastathogrAyAM zvapAka iti kIrtyate । vaidehakena tvambaSThyAmutpanno veNa ucyate ॥ 19 ॥
hk transliteration by Sanscript