XS-0: a self-explanatory school computer. - Jürg Nievergelt; Hans-Peter Frei; Helmar Burkhart; C. Jacobi; Bernhard Plattner; Hirotsugo Sugaya; B. Weibel; J. Weydert (ACM SIGCSE Bull., 1978)

XS-1: An Integrated Interactive System and Its Kernel. - G. Beretta; Helmar Burkhart; Peter Fink; Jürg Nievergelt; Jan Stelovsky; Hirotsugo Sugaya (ICSE, 1982)

Can an Operating System Support Consistent User Dialogs? Experience with the Prototype XS-2. - Jan Stelovsky; Jürg Nievergelt; Hirotsugo Sugaya; Edoardo S. Biagioni (ACM Annual Conference, 1985)

Command Language vs. Menus or Both? - Jan Stelovsky; Hirotsugo Sugaya (Software-Ergonomie, 1985)

A System for Specification and Rapid Prototyping of Application Command Languages. - Jan Stelovsky; Hirotsugo Sugaya (IEEE Trans. Software Eng., 1988)