Historie Jednokolek -

Většina zdrojů vychází ze stejné stránky - http://www.douglas-self.com/

Jednokolka ve 3D - https://tajtheguy.artstation.com/projects/mD39eY

zdroje:
https://www.impactlab.com/2006/11/27/history-of-the-worlds-craziest-invention-the-monowheel-with-amazing-pics/
jednokolka ke koupi- https://www.wheelsurf.nl/wheelsurf-2014.html

Patenty: https://patents.google.com/patent/US611534A/en?oq=US611%2c534

Monowheel 1869 https://www.impactlab.com/2006/11/27/history-of-the-worlds-craziest-invention-the-monowheel-with-amazing-pics/

douglas-self – monowheel part 1 a 2:
http://www.douglas-self.com/MUSEUM/TRANSPORT/motorwhl/motorwhl.htm
http://www.douglas-self.com/MUSEUM/TRANSPORT/motorwhl/motorwhl2.htm