@InProceedings{Koz90,
    Author       = "Kozen, D.",
    Year         = "1990",
    Title        = "{On Kleene Algebras and Closed Semirings}",
    Editor       = "Rovan, B.",
    BookTitle    = "{Proceedings of the Mathematical Foundations of Computer Science}",
    Place        = "Banska Bystrica, Czechoslovakia",
    Series       = "Lecture Notes in Computer Science",
    Number       = "452",
    Pages        = "26-47",
    Publisher    = "Springer-Verlag",
    Comment      = ""
}