@book{10018,
	author = {Weitzel, R L and ASTM},
	title = {Methods and Measurements of Periphyton Communities: a review},
	publisher = {ASTM,},
	year = {1979.},
	address = {USA:},
	url = {http://books.google.com.pk/books/about/Methods_and_Measurements_of_Periphyton_C.html?id=eEVRAAAAMAAJ&redir_esc=y}
}