This is for Mathematica.
1) list of geocentric <> geodetic <> XYZ related equations*
2) quick plots using them (3d poly globe)
3) wikipedia article summarizing the above
4) one equation is by author of this paper. shows that using (new) geometry observation, Heiskanen and Moritz or Ferrari equations were not necessary as the problem is not inheirently recursive as they suggested. (see article)
*gleened from many onlne sources. file geodetic-geodesic is same, improperly named...