sentences:  Apart from its armed struggle PRT maintained an open mass front, the trade union organization "Corriente de Integración Sindical".In 1984 PRT entered into the 'Trilateral', a cooperation between the National Liberation Army (ELN), the Revolutionary Integration Movement - Free Fatherland (MIR-PL) and PRT.Amongst other things, the Trilateral resulted in coordination of mass movement activities, leading up the formation of "¡A Luchar!"