APA
Council of Europe, Studies and Texts Series 13, . (1989). Regional transport. Conference, Cologne (Federal Republic of Germany), 31 May - 2 June 1989. Working documents and conclusions. Strasbourg: Council of Europe.
Chicago
Council of Europe, Studies and Texts Series 13, . 1989. Regional transport. Conference, Cologne (Federal Republic of Germany), 31 May - 2 June 1989. Working documents and conclusions. Strasbourg: Council of Europe.
Harvard
Council of Europe, Studies and Texts Series 13, . (1989). Regional transport. Conference, Cologne (Federal Republic of Germany), 31 May - 2 June 1989. Working documents and conclusions. Strasbourg: Council of Europe.
MLA
Council of Europe, Studies and Texts Series 13, . Regional transport. Conference, Cologne (Federal Republic of Germany), 31 May - 2 June 1989. Working documents and conclusions. Strasbourg: Council of Europe. 1989.