Hi,
I wrote an application which detects a square within an image. To give you a good understanding of how such an image containing such a square, in this case a marker, could look like:

What I get, after the detection, are the coordinates of the four corners of my marker. Now I don't know how to display an object on my marker. The object should have the same rotation/angle/direction as the marker.

Are there any papers on how to achieve that, any algorithms that I can use that proofed to be pretty solid/working?

It doesn't need to be a working solution, it could be a simple description on how to achieve that or something similar. If you point me at a library or something, it should work under linux, windows is not needed but would be great in case I need to port the application at some point. I already looked at the ARToolkit but they you camera parameter files and more complex matrices while I only got the four corner points and a single image instead of a whole video / camera stream.