Cardiotonic agents. 1. Novel 8-aryl substituted imidazo [1, 2-a]-and-[1, 5-a] pyridines and imidazo [1, 5-a] pyridinones as potential positive inotropic agents - Davey, D; Erhardt, P; Lumma, W; Wiggins, J; Sullivan, M; Pang, D; Cantor, E (J Med Chem, 1987)