+\bibitem{haralick1987image}
+Robert~M Haralick, Stanley~R Sternberg, and Xinhua Zhuang.
+\newblock Image analysis using mathematical morphology.
+\newblock {\em Pattern Analysis and Machine Intelligence, IEEE Transactions
+ on}, (4):532--550, 1987.
+
+\bibitem{snakegvf06}
+Zhiyu He and Falko Kuester.
+\newblock Gpu-based active contour segmentation using gradient vector flow.
+\newblock In George Bebis, Richard Boyle, Bahram Parvin, Darko Koracin, Paolo
+ Remagnino, Ara Nefian, Gopi Meenakshisundaram, Valerio Pascucci, Jiri Zara,
+ Jose Molineros, Holger Theisel, and Tom Malzbender, editors, {\em Advances in
+ Visual Computing}, volume 4291 of {\em Lecture Notes in Computer Science},
+ pages 191--201. Springer Berlin Heidelberg, 2006.
+