  In previous work we described how the process algebra based language PSF can
be used in software engineering, using the ToolBus, a coordination architecture
also based on process algebra, as implementation model. In this article we
summarize that work and describe the software development process more formally
by presenting the tools we use in this process in a CASE setting, leading to
the PSF-ToolBus software engineering environment. We generalize the refine step
in this environment towards a process algebra based software engineering
workbench of which several instances can be combined to form an environment.
