Please,

I need to find the x,y,z coordinates of the fermat point (P) of the triangle formed by three points A, B, C, for each of which I know the x,y,z coordinates. That, is Px, Py, Pz, as a function of Ax, Ay, Az, Bx, By, Bz, Cx, Cy, and Cz.

This is not astronomy: I need it for some stuff on phylogenetics (biology).

Thanks a lot in advance...

--Golo