Just noticed the following which contains some
related songs:

"1936 The Spanish Revolution" book + two 3" CDs
AK Press (San Francisco/Edinburgh), 1997
(reissue of 1986 book & 2 7" singles)

This is a collection of photographs of the Anarchist revolutionaries
actions in the Spanish Civil War.

There are short essays interspersed:
Revolution
The Collectives
Culture
The Front
The End
Afterword

not complementary to the Soviets.

The two 3" CD's contain the following songs which
are performed by THE EX:

THEY SHALL NOT PASS
EL TREN BLINDADO

AY CARMELA
PEOPLE AGAIN

Best wishes, Thomas.