L.  Maier-Hein, Mersmann, S., Kondermann, D., Stock, C., Kenngott, H., Sanchez, A., Wagner, M., Preukschas, A., Wekerle, A. - L., Helfert, S., Bodenstedt, S., and Speidel, S., ?Crowdsourcing for reference correspondence generation in endoscopic images?, in MICCAI, 2014.