1. Abd-el-Malek Y, Hosny I and Emam N F 1974 Evaluation of media used for enumeration of denitrifying bacteria. Zen- tralbl. Bakteriol. Parasitenkd. Infektionski Hyg$12 Abt. 415- 421.
2. Aulakh M S, Rennie D A and Paul E A 1982 Gaseous nitrogen from cropped and summer-fallowed soils. Can. J. Soil Sci. 62, 187 – 196.
3. Balderston W L, Sherr B and Payne W J 1976 Blockage by acetylene of nitrous oxide reduction in Pseudomonas perfectomarinus. Appl. Environ. Microbiol. 31, 504 – 508.
4. Betlach M R 1982 Evolution of bacterial denitrification and denitrifier diversity. Antonie van Leeuwenhock J. Microbiol. 48, 585 – 607.
5. Blackmer A M, Robbins S G and Bremner J M 1982 Diurnal variability in rate of emission of nitrous oxide from soils. Soil Sci. Soc. Am. J. 46, 937 – 942.