We would like to acknowledge the following:
- http://zarb.org/~gc/html/libpng.html: for providing a good example on how to use the libpng
- http://www.hazelwhorley.com/textures.html: for providing good skybox textures
- http://www.vwi.tu-dresden.de/~treiber: for providing some inspiration
If you feel that you deserve an acknowledgment (which is possible), feel free to make a request here.