Formal and Natural Computing Essays Dedicated to Grzegorz Rozenberg - Brauer, Wilfried; Brauer, Wilfried; Ehrig, Hartmut; Ehrig, Hartmut; Karhumäki, Juhani; Karhumäki, Juhani; Salomaa, Arto K.; Salomaa, Arto K. (Springer Berlin Heidelberg : Imprint: Springer, 2002)