Skandapurana 1.4.38.201

1.4.38.201

vārāhaṃ dvādaśaṃ caiva skāṃdaṃ caiva trayodaśam..
caturdaśaṃ vāmanaṃ ca kaurmaṃ paṃcadaśaṃ smṛtam.. 40.201 ..

the Vārāha as the twelfth, and the Skānda as the thirteenth; / the Vāmana is the fourteenth, and the Kūrma is remembered as the fifteenth;