Excursions in Non-Euclidian Geometry, Saul Stahl, 2019.

Hyperbolic Centroids of Some Regions, Saul Stahl, 2019.

Mass in Hyperbolic 3-Space, Saul Stahl, 2019.

Mass in Hyperbolic Geometry, Saul Stahl, 2019.

Planetary Orbits in Constant Curvature Planes, Saul Stahl, 2019.