https://toolstud.io/photo/aspect.php

http://aarmstrong.org/content/aspect_ratio_calc.php

http://www.moving-picture.com/documents/FilterRendering.pdf

https://cmivfx.com/store

For over 10 years, cmiVFX has been providing valuable lessons in both real world and experimental techniques that define the very fabric of the Visual Effects Industry. This training material cannot be found anywhere else because they provide you with knowledge from mentors who have contributed to a number of the world’s most famous movies, advertisements, and media.

http://kirillmuzykov.com/unity-4-6-new-gui-tutorial/