Gudyreva, E. M.; Tsalenko, M. Sh. An algebra of hierarchical data structures. (English. Russian original) Zbl 0728.68051 Sov. J. Comput. Syst. Sci. 27, No. 1, 67-82 (1989); translation from Izv. Akad. Nauk SSSR, Tekh. Kibern. 1988, No. 5, 51-71 (1988). MSC: 68P15 08A70 PDFBibTeX XMLCite \textit{E. M. Gudyreva} and \textit{M. Sh. Tsalenko}, Sov. J. Comput. Syst. Sci. 27, No. 1, 67--82 (1989; Zbl 0728.68051); translation from Izv. Akad. Nauk SSSR, Tekh. Kibern. 1988, No. 5, 51--71 (1988)
Babushkin, M. A.; Tsalenko, M. Sh. Relational algebras with truth estimates. (English. Russian original) Zbl 0728.68049 Sov. J. Comput. Syst. Sci. 27, No. 2, 103-108 (1989); translation from Izv. Akad. Nauk SSSR, Tekh. Kibern. 1988, No. 6, 125-132 (1988). MSC: 68P15 03G25 03B20 08A70 03E72 PDFBibTeX XMLCite \textit{M. A. Babushkin} and \textit{M. Sh. Tsalenko}, Sov. J. Comput. Syst. Sci. 27, No. 2, 103--108 (1989; Zbl 0728.68049); translation from Izv. Akad. Nauk SSSR, Tekh. Kibern. 1988, No. 6, 125--132 (1988)