I suppose, that there are more modern sources, but Stoljar and Kondratjev's Alt-Benoni Verteidigung spends 12-13 pages on it. Indeed there are several transpositions from/to the Pirc.
Austrian Attack: 1.e4 d6 2.d4 Nf6 3.Nc3 g6 4.f4 Bg7 5.Nf3 c5 6.d5 is the same as 1.d4 c5 2.d5 d6 3.e4 Nf6 4.Nc3 g6 5.f4 Bg7 6.Nf3.
Classical Pirc: 1.e4 d6 2.d4 Nf6 3.Nc3 g6 4.Nf3 Bg7 5.Be2 o-o 6.o-o c5 7.d5 is the same as 1.d4 c5 2.d5 d6 3.e4 Nf6 4.Nc3 g6 5.Nf3 Bg7 6.Be2 o-o (Na6!?) 7.o-o.
There are a few others too: as soon as White answers c7-c5 in the Pirc with d4-d5 you are there.

Personally I have always felt, that the Austrian Attack is most dangerous. It is a serious omission of most books on the Pirc, that they do not mention White's 6.d5 against the important line 5...c5.

It is also important, that in the Schmid-Benoni White has the option of 6.Bb5+, which is obviously not the case with the Classical Pirc.

Hello chessfriends,

i am looking for theory on the Schmid-Benoni:

1.d4 Nf6
2.Nf3 g6
3.Nc3 c5
4.d5 Bg7
5.e4 d6

In which book is this system theme and what is whites best strategy ???

Thanks for your help!