Issue 84/1997 Silvano Martello, From the Editor Renata Mansini, Maria Grazia Speranza, Effective linear programming heuristics for a portfolio selection problem Laura Amarone, Luciano Cinfrignini, Paul Harris, Beniamino Paoletti, Sergio Tommasi di Vignano, HiCAT: a market share, simple connection-based timetable generation model for an airline Vito Ozzola, Sandro Poli, A decision method to evaluate oil and gas development systems