The forty-second category mainly includes theoretical and practical services provided by people, individuals or collectives involved in complex field activities; These services are provided by chemists, physicists, engineers and computer programmers. Specifically, this category includes:-services provided by engineers engaged in assessment, estimation, research and reporting in the field of science and technology; -Scientific research services for medical purposes; -Computer and technical services to protect the security of computer data, personal and financial information, and computer and technical services to monitor unauthorized access to data and information. In particular, this category does not include:-commercial research and development (category 35); -Word processing and computer file management (category 35); -Finance and financial evaluation (category 36); Mining and oil exploitation (category 37); -Computer (hardware) installation and maintenance services (category 37); -Services provided by professionals such as doctors, veterinarians and psychoanalysts (category 44); Medical services (category 44); -Landscape design (category 44); -Legal services (category 45).