Gottlob, G., Kappel, G., & Schrefl, M. (1995). The Evolving Algebra Semantics of Class and Role Hierarchies. Springer.
Lua i Stíl Chicago (17ú heag.)Gottlob, G., G. Kappel, agus M. Schrefl. The Evolving Algebra Semantics of Class and Role Hierarchies. Springer, 1995.
Lua MLA (9ú heag.)Gottlob, G., et al. The Evolving Algebra Semantics of Class and Role Hierarchies. Springer, 1995.
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