@book{58485,
	author = {"Tokeo, Koyana and Chittana, Chammek."},
	title = {Nitrogen application technology for tropical rice as determined by firld experiments using 15 N tracer technique},
	publisher = {"Trop.Agric. Res.Centre, Min.of Agric.& Forestry"},
	year = {Japan},
	address = {1973}
}