17th Congress International Friends of Nature : : Tagungsunterlagen.

MLA

17th Congress International Friends of Nature : Tagungsunterlagen. S.l.: NFI, 1999.

APA

(1999). 17th Congress International Friends of Nature : Tagungsunterlagen. S.l.: NFI.

Chicago

17th Congress International Friends of Nature: Tagungsunterlagen. S.l.: NFI, 1999.