Manusmriti
एतास्तिस्रस्तु भार्यार्थे नोपयच्छेत् तु बुद्धिमान् । ज्ञातित्वेनानुपेयास्ताः पतति ह्युपयन्नधः ॥ १७२ ॥
A wise man should not take as his wife any of these three; they must not be wedded because they are (Sapinda-) relatives, he who marries (one of them), sinks low.
english translation
etAstisrastu bhAryArthe nopayacchet tu buddhimAn । jJAtitvenAnupeyAstAH patati hyupayannadhaH ॥ 172 ॥
hk transliteration by Sanscript