@article {30276,
	title = {A mathematical model for orientation data from macroscopic folds},
	volume = {8},
	year = {1976},
	pages = {549-559},
	publisher = {Mathematical Geology},
	url = {http://www.springerlink.com/content/j0j3vn05q038472g/fulltext.pdf},
	author = {Kelker, D. and Langenberg, C. W.}
}
