Citation: Wyckoff, R. W. G. (1935). Page 55 from the second edition supplement of The Structureof Crystals by Wyckoff R W G. published by Reinhold Publishing Corporation, INC,Camden, N. J. in 1935 & http://jcrystal.com/steffenweber/gallery/StructureTypes/st4.html. The second edition supplement of The Structure of Crystals, , pp. 55-55.