1. 3-D Printing for Beginners.com. (2014). How to make DIY filament for your 3-D printer. Retrieved June 2, 2014, from http://3dprintingforbeginners.com/how-to-make-diy-filament-for-your-3d-printer/
2. 3-D printing: The new industrial revolution;Berman;Business Horizons,2012
3. When customers get clever: Managerial approaches to dealing with creative consumers;Berthon;Business Horizons,2007
4. Brown, H. J. (2012, January 17). Additive versus subtractive manufacturing. Retrieved June 2, 2014, from http://www.dmass.net/2012/01/17/additive-versus-subtractive-manufacturing/
5. Brown, S. (2013). 3D printed handguns will be outlawed in New York, other states soon to follow. Digital Afro. Retrieved from http://www.digitalafro.com/3d-printed-handguns-will-be-outlawed-in-new-york-other-states-soon-to-follow/