Manava Dharmashastra 2.16

2.16

niṣekādiśmaśānānto mantrair yasyodito vidhiḥ
tasya śāstre 'dhikāro 'smiñ jñeyo nānyasya kasya cit //

Know that he for whom (the performance of) the ceremonies beginning with the rite of impregnation (Garbhadhana) and ending with the funeral rite (Antyeshti) is prescribed, while sacred formulas are being recited, is entitled (to study) these Institutes, but no other man whatsoever.