Pahlavi Texts, Part IV (SBE37), E.W. West, tr. , at sacred-texts.com
It has been already shown, in Dk. VIII, Chap. XLVI, 1 n, that the whole of this Nask is probably still extant in the Yasna and Vîspêrad. About half of the present Yasna appears to consist of five-sixths of this Stôd-yast, to which have been added three
fargards of the Bakŏ (Nask III), with the Hôm and Srôsh Yasts, extracted probably from the Bakân-yast (Nask XIV), and the greater part of the Âtas and Âbân Nyâyises; the whole collection being provided with an introductory and concluding ritual, compiled from other sources, to form the complete ceremonial liturgy of the present Yasna.
There appears to be no sufficient evidence, either internal or external, for ascribing this collection of the liturgy to so late a date as the end of the ninth century, when the compilation of the Dinkard was completed. It is therefore safer, for the present, to assume that the Stôd-yast existed for a long period as a separate Nask (the form described by the Dinkard), even after the greater part of its text had been incorporated with others to form the collected liturgy now known as the Yasna.
Besides the fragments which are specially attributed to particular Nasks, there are also a few writings which closely resemble the Nasks, or their fragments, in general character, but which can hardly be traced to their actual source by means of the accounts given in the Dinkard. Thus, the Aogemadaêkâ might perhaps be supposed to have been extracted from the Baris (see Dk. VIII, Chap. IX, 18), if it did not contain a few Avesta quotations from the Yasna, Vendîdâd, and Yasts. While the quotations from the Ashem-staota, given in Vig. pp. 89, 90, 125-129, 177, 178, are difficult to trace, owing to the name of their source.
487:1 The actual extent of those portions of the Yasna and Vîspêrad which appear to have constituted this Nask, may be estimated at about 12,500 Avesta and 22,400 Pahlavi words.