Bibliography
[1] Schematron, Resource Description for Schematron (web page), Rick Jelliffe, Computing Centre, Academia Sinica, Taipei, http://purl.oclc.org/dsdl/schematron
[2] XCSL, XML Constraint Specification Language, JosÚ Carlos Leite Ramalho, Department of Informatics, School of Engineering, University of Minho, http://www.di.uminho.pt/~jcr/PROJS/xcsl-www/