1. A scheme for three-dimensional display by automatic fabrication of three-dimensional model;Kodama;IEICE Trans Electron,1981
2. Hull CW Apparatus for production of three-dimensional objects by stereolithography
3. The Economist A third industrial revolution 2012 http://www.economist.com/node/21552901
4. Three dimensional printing: rapid tooling and prototypes directly from a CAD model;Sachs;J Manuf Sci Eng,1992