APA
UNITED NATONS ENVIRONMENT PROGRAMME, UNITED NATONS ENVIRONMENT PROGRAMME, . (1999). Annual report 1998. s.l: UNEP UN.
Chicago
UNITED NATONS ENVIRONMENT PROGRAMME, UNITED NATONS ENVIRONMENT PROGRAMME, . 1999. Annual report 1998. s.l: UNEP UN.
Harvard
UNITED NATONS ENVIRONMENT PROGRAMME, UNITED NATONS ENVIRONMENT PROGRAMME, . (1999). Annual report 1998. s.l: UNEP UN.
MLA
UNITED NATONS ENVIRONMENT PROGRAMME, UNITED NATONS ENVIRONMENT PROGRAMME, . Annual report 1998. s.l: UNEP UN. 1999.