There exist optimal symmetric equilibria in the Green-Porter model [5, 8] having an elementary intertemporal structure. Such an equilibrium is described entirely by two subsets of price space and two quantities, the only production levels used by ﬁrms in any contingency. The central technique employed in the analysis is the reduction of the repeated game to a family of static games.
Abreu, Dilip; Pearce, David G.; and Stacchetti, Ennio, "Optimal Cartel Equilibria with Imperfect Monitoring" (1984). Cowles Foundation Discussion Papers. 966.