Non-Euclidean Geometry - An introduction to Non-Euclidean Geometry written by Jacob Graves as an MSc project in 1997. cvu.strath.ac.uk/courseware/info/noneucgeom.html
Non-Euclidean Geometry - A historical account with links to biographies of some of the people involved. www-groups.dcs.st-andrews.ac.uk/~history/HistTopics/Non-Euclidean_geometry.html
Non-Euclidean Geometry - Mathematics and the Liberal Arts - A resource for student research projects and for teachers interested in using the history of mathematics in their courses. math.truman.edu/~thammond/history/NonEuclideanGeometry.html
Smarandache Geometries - Having at least one smarandachely denied axiom: validated and invalidated; or invalidated in at least two distinct ways. Discussion groups and meetings. www.gallup.unm.edu/~smarandache/geometries.htm
Spherical Trigonometry, Arc Distance Formula - Finding the shortest distance between two points on the earth given latitude and longitude. Download ARC_CALC_3, Microsoft Excel version, A Spherical Triangle Calculator by James Q. Jacobs. www.jqjacobs.net/astro/arc_form.html