« System of twisty puzzles » (consulté le ) : « Helicopter Cube was designed and built by Adam G. Cowan (Puzzlemaster42) and Katsuhiko Okamoto (Katsuhiko) in 2007 »
mefferts.com
« Helicopter Cubes Black body », Mèffert's (consulté le ) : « The Helicopter Cube was conceived by Adam G. Cowan in 2005, but wasn’t built until 2006, when Adam discovered that 3D printing could be used to realize the parts. »
Goetz Schwandtner, « Extremely Puzzling » (consulté le ) : « Helicopter Cube black ... By Adam Cowan »
tomvanderzanden.nl
Tom van der Zanden, « Curvy Copter » (consulté le ) : « The Curvy Copter is my most popular puzzle yet. It is a variation on Adam G. Cowan's Helicopter Cube. »
