1. K. Peeters, “Introducing Cadabra: A Symbolic Computer Algebra System for Field Theory Problems,” hepth/0701238; Jaunary 2007, http://www.aei.mpg.de~peekas/cadabra/cadabra_hep.ps .
2. K. Peeters, “Cadabra: Reference Guide and Tutorial,” Preprint AEI-2006-038 (2001–2007); http://www.aei.mpg.de~peekas/cadabra/cadabra.ps.