Application development by endusers. - R. Kogon; E. Keppel; D. Kropp (IBM Symposium: Interactive Systems, 1976)

Interactive Programming by End-users. - E. Keppel; D. Kropp (ACM Annual Conference, 1977)

Working set size reduction by restructuring APL workspaces. - D. Kropp; H. Wrobel (ECI, 1978)

Text Field Indexing. - D. Kropp; Hans-Jörg Schek; Georg Walch (Datenbanktechnologie, 1979)

A graph structured text field index based on word fragments. - D. Kropp; Georg Walch (Inf. Process. Manag., 1981)