I was wondering if anyone may have useful links to the mathematics used by the F9R that allowed it to fly back to LZ-1 and land successfully. I'm hoping to find some papers that will give the broadest (i.e. easiest) mathematical approximation, where the F9R is treated as a point-mass (i.e. no need to model the rigid-body dynamics, cold-gas thrusters, grid-fin aerodynamics or nozzle thrust vectoring).

I'd like to be able to build a 3D Earth model and use some differential equations to model the F9R's motion, but would also like to be able to model a simplified version of its flyback and landing maneuver to be incorporated into the DEs.

Any help would be greatly appreciated, thanks!

EDIT: Having found a webpage listing Lars Blackmore's (SpaceX flyback engineer) publications (http://web.mit.edu/larsb/www/), it seems that he did a lot of work on powered descent guidance for Mars landings. I'm assuming this has been generalized for use in the Falcon 9 flyback maneuver. Unfortunately optimization isn't one of my fortes.