Trotsky and the POUM
- Article from Revolutionary History on the political relationship and conflict between Trotsky and the POUM.
- http://www.marxists.org/history/etol/document/spain/spain03.htm

Stalinism and the POUM in the Spanish Revolution
- Article from Revolutionary History.
- http://www.marxists.org/history/etol/document/spain/spain02.htm

POUM - Workers Party of Marxist Unification
- Background on the party founders in 1935.
- http://www.spartacus.schoolnet.co.uk/SPpoum.htm

The P.O.U.M. in Spain
- Critical contemporary article by Albert Weisbord.
- http://www.weisbord.org/POUM.htm

Andres Nin
- Biographical sketch with links of the co-founder of the POUM (Marxist Party of Unification) and leader in the civil war.
- http://www.spartacus.schoolnet.co.uk/SPnin.htm