[1] The work is no longer extant, but its content can be reconstructed from lengthy references in Book 9 of the Denkard and the parts still contained in Yasna 19-21.
On the other hand, the Bagan of Yasna 19-21 is probably derived from baγąm found in the three Gathic manthras, namely the Ahuna Vairya, the Ashem Vohu and the Yenghe hatam.
Edward William West estimates, that the Bag nask consisted of ca.
[10] These fragards contain commentaries on the Ahuna Vairya, the Ashem Vohu and the Yenghe hatam manthra.
The rest is now lost, but according to Book 9 of the Denkard, these fragards contained commentaries on the Gathas and the Airyaman ishya manthra.