CrocoPat 2.1 Introduction and Reference Manual
  CrocoPat is an efficient, powerful and easy-to-use tool for manipulating relations of arbitrary arity, including directed graphs. This manual provides an introduction to and a reference for CrocoPat and its programming language RML. It includes several application examples, in particular from the analysis of structural models of software systems. 
Dirk Beyer (University of California, Berkeley), Andreas Noack   (Brandenburg University of Technology)