Specifications XML 1.0, XHTML 1.0, XHTML 1.1, XSLT 1.0 (in Russian) in a help-fayle windows (format chm). Useful for novice web-masters (and experienced not hurt). Official (free) version of the English language is www.w3.org site as html or text-file.
This help-file is a convenient navigation system + search words.