What is the standing of the book "The Difference Between the Narration of Warsh and Hafs" and what is the extent of the soundness of its author's chain of transmission (sanad) in the Qira'at (recitations)?

The aforementioned book is excellent in its field, and its author is one of the scholars of the Quran. He has granted authorization (ijazah) to a number of reciters with an unbroken chain of transmission (sanad muttasil). The fact that the author of "Al-Halaqat Al-Mudiyyat" did not mention him does not diminish his standing, because he did not cover all the reciters of Mauritania. In his book, he only mentioned the chain of teachers of Al-Dunbuj ibn Mu'awiyah. So, Al-Dunbuj did not mention A'mar because he was not among his teachers, and the author of "Al-Halaqat" did not claim to have covered all those with chains of transmission.