Yasuhiro Kurokawa
      Singularities of asymptotic lines on surfaces in R^4
      International Journal of Contemporary Mathematical Sciences, Vol. 11, 2016, no. 7, 301-311
      http://dx.doi.org/10.12988/ijcms.2016.6526

Copyright © 2016 Yasuhiro Kurokawa. This article is distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.