Asymptomatic pulmonary embolism in patients with deep vein thrombosis. Is it useful to take a lung scan to rule out this condition? - Monreal, M; Rey-Joly Barrosa, C; Ruiz-Manzona, J; Salvador-Tarrason, R; Lafoz-Laval, E; Viver-Manresa, E (J Cardiovasc Surg (Torino), 1989)