To create the launch icon for this app I used and modified the following two images, the first of which is protected by the Creative Commons Attribution-Share Alike 3.0 Unported License. The second of which is available for non-commercial use by Custom Icon Design.
Image number 1: here
Creator of Image number 2: here
To create the launch icon for this app I used and modififed the following image of calculator, which is free to use and has no license
Image number 1: here.