Conference paperContracts: Specifying behavioral compositions in object-oriented systemsRichard Helm, Ian M. Holland, et al.ECOOP 1990
PaperIntegrating information retrieval and domain specific approaches for browsing and retrieval in object-oriented class librariesRichard Helm, Yoëlle S. MaarekACM SIGPLAN Notices
Conference paperConstraint-based query optimization for spatial databasesRichard Helm, Kim Marriott, et al.SIGMOD/PODS/ 1991