 They were the entity-relationship approach of Peter Chen (1976) and SADT of Douglas T. Ross (1977), the one concentrate on the information view and the other on the function view of business entities.These first methods have been followed end 1970s by numerous methods for software engineering, such as SSADM, Structured Design, Structured Analysis and others.Specific methods for enterprise modelling in the context of Computer Integrated Manufacturing appeared in the early 1980s.