The Community Z Tools (CZT) project is building a set of tools for editing, typechecking and animating formal specifications written in the Z specification language, with some support for Z extensions such as Object-Z, Circus, and TCOZ. These tools are all built using the CZT Java framework for Z tools.
The OBJ languages are broad spectrum algebraic programming and specification languages, based on order sorted equational logic, possibly enriched with other logics (such as rewriting logic, hidden equational logic, or first order logic), and providing the powerful module system of parameterized programming...All the OBJ languages are rigorously based upon a logical system; more precisely, they are logical languages, in the sense that their programs are sets of sentences in some logical system, and their operational semantics is given by deduction in that logical system.
S. Dascalu, and P. Hitchcock. SAC '02: Proceedings of the 2002 ACM symposium on Applied computing, page 1014--1020. New York, NY, USA, ACM Press, (2002)