This Document Type Definition specifies the Czech National Corpus SGML markup scheme, as used (with extensions) in various derived corpora, most notably in the Prague Dependency Treebank. The pure DTD file is called csts.dtd and the declaration file is called csts.dcl; there is also a version for direct use with the nsgmls software (csts.doctype), and a description file which can be fed into the dtd2html program, csts.desc, which produced these HTML documentation pages.