@book {592,
	title = {Changes in the Duch bryophyte flora and air pollution},
	series = {Dissertationes Botanicae},
	volume = {Band 194},
	year = {1992},
	publisher = {J. Cramer},
	organization = {J. Cramer},
	address = {Berlin},
	author = {Greven, H.C.}
}
