APA引文

United Nations Environment Programme Industry and Environment. (1998). Ecolabels in the tourism industry. UNEP.

Chicago Style (17th ed.) Citation

United Nations Environment Programme Industry and Environment. Ecolabels in the Tourism Industry. Paris, France: UNEP, 1998.

MLA引文

United Nations Environment Programme Industry and Environment. Ecolabels in the Tourism Industry. UNEP, 1998.

警告：這些引文格式不一定是100％准確.