Informal and formal methods can play complementary roles in object oriented software development. In this paper we present our work on integrating UML static models with the algebraic specification style. In previous work, a model for the definition of reusable components and a rigorous method for object oriented software reusability have been introduced. Our current goal is to map design artifacts to object oriented code. Since an integrated method requires common structuring mechanisms for object oriented models and algebraic specifications, the GSBLOO language has been defined. This language enriches GSBL with constructs that allow us to express different kinds of UML relations (dependencies, associations, generalizations and realizations).