* http://reprap.org/wiki/Print_Troubleshooting_Pictorial_Guide
* [http://nothinglabs.blogspot.ch/2013/11/3d-printed-hook-loop-fasteners.html 3D printed 'velcro']
* [http://www.kickstarter.com/projects/172237528/improved-3d-printer-extruder-allows-more-plastic-o Improved 3D printer extruder (for PVC and other plastics)]