THIS PART OF THE BOOK DEALS WITH THE FOLLOWING: MATHEMATICAL SIMULATION OF VARIABLE CONDITIONS IN GROUND WATER, CUENCA,J; MATHEMATICAL MODELS FOR SIMULATING EARTHQUAKES, SAMARTIN,A; GENERAL PRINCIPLE OF THE SIMULATION OF OPERATIONAL SYSTEMS, PROGRAMMING LANGUAGES, CUENCA,J; SIMULATION OF THE OPERATION OF HYDRAULIC RESOURCES SYSTEM, CUENCA,J; TEST SIMULATION. ESTIMATION OF STATISTICAL PARAMETERS, MARTIN,V; USE OF SIMULATION FOR THE CONTROL OF PROJECTS, CERCOS,R; SIMULATION OF URBAN ROAD TRAFFIC, SANCHEZ,V; APPLICATION OF SIMULATION TO PORT TRAFFIC. SIMULATION OF HARBOUR OPERATIONS, NAVACERRADA,J; APPLICATION OF SIMULATION TO HARBOUR TRAFFIC. SIMULATION OF THE OPERATION OF A CRUDE OIL HARBOUR, FERRER,I. SIMULATION MODEL FOR CALCULATING GROUND PERSONNEL IN AIRPORTS, GASCO,JL. SEE ALSO IRRD ABSTRACTS NOS 103509 AND 103511.