The Zend-Avesta, Part 2 (Sacred Books of the East, Vol. 23) (1883) - Page 17

In India, the Sîrôzah is recited in honor of the dead: on the thirtieth day after death, on the thirtieth day of the sixth month, on the thirtieth day of the twelfth month, and then every year on the thirtieth day from the anniversary (Anquetil, Zend-Avesta, II, 315).

The correspondence between the formulas of the Sîrôzah and the Yasts is as follows:

Day	Invocation	Corresponding Yast
1.	Ormazd	Ormazd Yast (I, 1-23)
2.	Bahman	Bahman Yast (I, 24-33)
3.	Ardibehest	Ardibehest Yast (III)
4.	Shahrêvar
5.	Sapendârmad
6.	Khordâd	Khordâd Yast (IV)
7.	Murdâd
8.	Dai pa Âdar
9.	Âdar
10.	Âbân	Âbân Yast (V)
11.	Khorshêd	Khorshêd Yast (VI)
12.	Mâh	Mâh Yast (VII)
13.	Tîr	Tîr Yast (VIII)
14.	Gôs	Gôs Yast (IX)
15.	Dai pa Mihir
16.	Mihir	Mihir Yast (X)
17.	Srôsh	Srôsh Yast (XI)
18.	Rashn	Rashn Yast (XII)
19.	Farvardîn	Farvardîn Yast (XIII)
20.	Bahrâm	Bahrâm Yast (XIV)
21.	Râm	Râm Yast (XV)
22.	Bâd
23.	Dai pa Dîn
24.	Dîn	Dîn Yast (XVI)
25.	Ard	Ashi Yast (XVII)
26.	Âstâd	Âstâd Yast (XVIII)
27.	Âsmân
28.	Zemyâd	Zemyâd Yast (XIX)
29.	Mahraspand
30.	Anêrân

The Yasts that have been lost are, therefore, those dedicated to Khshathra-vairya, Spenta-Ârmaiti, Ameretâṭ, Âtar, Vâta, Asman, Mãthra-Spenta, and Anaghra raokau. The second Yast, or the Yast of the seven Amshaspands, does not appear to have been an independent Yast; it was common to all seven Yasts devoted to the several