Pruppacher HR, Klett JD.
Microphysics of Clouds and Precipitation. Dordrecht, NL: Reidel Publishing Company; 1978 p. 715 pp.
Prairie YT, Duarte CM, Kalff J.
Unifying nutrient-chlorophyll relationships in lakes. . Canadian Journal of Fisheries and Aquatic Sciences . 1989 ;46:1176-1182.
PORG.
Ozone in the United Kingdom 1997. London: Department of the Environment; 1997.