1. Amacker, J. (1982), “Tree climbing stand”, Patent US/4331216, Amacker, Clinton, MS.
2. Boulevard, J. and Renaud, J.C. (2008), “POBOT: pole climbing robot”, IFMA Project, IFMA, Houston, TX.
3. Castelli, C. (1935), “Climber for poles of hard material”, Patent US/2009474.
4. Catalog Sibille Fameca Electric (2010), “Grimpette pour poteaux en bois (“Pole climber for wooden poles”)”, available at: www.sf‐electric.com/CLIENT/?menu=1&mode=3&id=4419.
5. Emery, W. and Shuff, H. (1949), “Machine for debarking and trimming either standing or felled tree trunks”, Patent US/2477922.