APA
United Nation G. O. . E. C. f. E., United Nation G. O. . E. C. f. E., . (1990). State of transboundary air pollution. New York: United Nation U S A.
Chicago
United Nation Government Of Economic Commission for Eurpoe, United Nation Government Of Economic Commission for Eurpoe, . 1990. State of transboundary air pollution. New York: United Nation U S A.
Harvard
United Nation G. O. . E. C. f. E., United Nation G. O. . E. C. f. E., . (1990). State of transboundary air pollution. New York: United Nation U S A.
MLA
United Nation Government Of Economic Commission for Eurpoe, United Nation Government Of Economic Commission for Eurpoe, . State of transboundary air pollution. New York: United Nation U S A. 1990.
