"The Bibliography of Linguistic Literature (BLL) is one of the most comprehensive linguistic bibliographies worldwide. It covers general linguistics with all its neighbouring disciplines and subdomains as well as English, German and Romance linguistics. The BLL dates back as far as 1971 and lists circa 500,000 bibliographic references. Furthermore, the BLL provides a hierarchically categorised thesaurus of domain-specific index terms in German and English. The BLL Thesaurus comprises more than 9,000 subject terms."