| AIE | Ala Izquierda Estudiantil (Left-Wing Students)
|
| ANERC | Asociación Nacional de Nuevos Emigrados Revolucionarios de Cuba (Association of New Revolutionary Emigrés from Cuba)
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| APRA | Alianza Popular Revolucionaria Americana (American Popular Revolutionary Alliance)
|
| ARG | Acción Revolucionaria Guiteras (Guiteras Revolutionary Action)
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| BOC | Bloque Obrero y Campesino (Workers' and Peasants' Bloc: Spain)
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| Comintern | Communist or Third International
|
| CC | Central Committee
|
| CDR | Comité de Defensa de la Revolución (Committee for the Defence of the Revolution)
|
| CNOC | Confederación Nacional Obrera de Cuba (National Labour Confederation of Cuba)
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| CPUSA | Communist Party of the United States of America
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| CROM | Confederación Regional Obrera Mexicana (Mexican Regional Labour Confederation)
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| CTC | Confederación de Trabajadores de Cuba (Workers' Confederation of Cuba)
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| DOI | Defensa Obrera Internacional (International Labour Defence)
|
| FCT | Federación Cubana del Trabajo (Cuban Labour Federation)
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| FI | Fourth International
|
| FOH | Federación Obrera de La Habana (Labour Federation of Havana)
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| ICL | International Communist League (Bolshevik-Leninists)
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| ILO | International Left Opposition
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| INRA | Instituto Nacional de Reforma Agraria (National Institute of Agrarian Reform)
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| KPD | Kommunistische Partei Deutschlands (German Communist Party)
|
| LOR | Liga Obrera Revolucionaria (Revolutionary Workers' League: Argentina)
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| M26J | Movimiento 26 de Julio (26th July Movement)
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| MAFUENIC | Comité de Manos fuera de Nicaragua (Hands Off Nicaragua Committee)
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| MNR | Movimiento Nacionalista Revolucionario Revolutionary Nationalist Movement: Bolivia)
|
| MR-13 | Movimiento Revolucionario 13 de Noviembre (13 November Revolutionary Movement: Guatemala)
|
| MSR | Movimiento Socialista Revolucionario (Revolutionary Socialist Movement)
|
| OCC | Oposición Comunista de Cuba (Communist Opposition of Cuba)
|
| ORI | Organizaciones Revolucionarias Integradas (Integrated Revolutionary Organisations)
|
Profintern
or RILU | Red International of Labour Unions
|
| PBL | Partido Bolchevique Leninista (Bolshevik Leninist Party)
|
| PCC | Partido Comunista de Cuba (Communist Party of Cuba)
|
| PCM | Partido Comunista de México (Communist Party of Mexico)
|
| POR | Partido Obrero Revolucionario (Revolutionary Workers' Party)
|
| POR(T) | Partido Obrero Revolucionario (Trotskista) (Revolutionary Workers' Party (Trotskyist))
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| POUM | Partido Obrero de Unificación Marxista (Workers' Party of Marxist Unification: Spain)
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| PRC(A) | Partido Revolucionario Cubano (Auténtico) (Cuban Revolutionary Party ('Genuine Revolutionaries'))
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| PSP | Partido Socialista Popular (Popular Socialist Party)
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| PURS | Partido Unificado de la Revolución Socialista (Unified Party of Socialist Revolution)
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| SGECC | Sindicato General de Empleados del Comercio de Cuba (General Commercial Workers' Union of Cuba)
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| SNOIA | Sindicato Nacional de Obreros de la Industria Azucarera (National Union of Sugar Industry Workers)
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| SWP(US) | Socialist Workers' Party (United States)
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| UFON | Unión Federativa Obrera Nacional (National Federative Labour Union)
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| UIR | Unión Insurreccional Revolucionaria (Revolutionary Insurrectionary Union)
|
| URC | Unión Revolucionaria Comunista (Communist Revolutionary Union)
|
| USec | United Secretariat of the Fourth International
|
