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Vāsiṣṭha
The Dharmasūtra of Vasiṣṭha forms an independent treatise and has no relationship with the Kalpasutra. The chapters of this text are divided in a way that resemble the practice of later Smritis. This Dharmasūtra has a unique characteristic, it cites the opinions of Manu at many places. This led scholars like Bühler among others to form a hypothesis that there must have been a Dharmasūtra of Manu.