¡No Pasaran! - Las Batallas por Madrid 1936-37 (1991)

Although the rules are dated 1991, the cover is dated 1995. I gather this is a reprint.

960 counters, rules in Spanish but with English translation provided.

This is the first in LudoPress' Serie Guerra Civil Española (volumen 1). Also in this series

Mallorca 1936
Balaguer 1938

and a soon to be released C.T.V. - Guadalajara 1937 (serie Guerra Civil Española volumen 2).

Adapted from LudoPress web site:

This series gives a detailed tactical-operational treatment to several battles of the civil conflict. The level of detail is high for aspects such as supply, combat or organic organization of divisions/army corps, but the system always uses mechanisms as simple and intuitive as possible.

The objective with this series was to give the Spanish Civil War a specific treatment. Until then, what most designers in Spain and abroad did to simulate SCW battles was simply to adapt systems designed for WW2 games. ¡No Pasarán! is a system specifically designed to show the peculiar features and differences of the civil war with respect to other conflicts, especially the First and Second World Wars.