Cita APA (7a ed.)

Programa de les Nacions Unides per a la Defensa del Medi. Industry and Environment. (1998). Ecolabels in the tourism industry. United Nations Environment Programme. Industry and Environment.

Cita Chicago Style (17a ed.)

Programa de les Nacions Unides per a la Defensa del Medi. Industry and Environment. Ecolabels in the Tourism Industry. Paris: United Nations Environment Programme. Industry and Environment, 1998.

Cita MLA (9a ed.)

Programa de les Nacions Unides per a la Defensa del Medi. Industry and Environment. Ecolabels in the Tourism Industry. United Nations Environment Programme. Industry and Environment, 1998.