Hee-Choul Kwon and  Heeyong Kwon,  Image Rotation Using an Augmented 2-Step Shear Transform.   journal   = {International Journal of Computer, Electrical, Automation, Control and Information Engineering}, [online]. World Academy of Science, Engineering and Technology. January 2017, vol. 121(1). 60 - 63[viewed 24 April 2018]. Available from: http://waset.org/publications/10006172.