1. Johansson, A.: Single grip harvester head felling and processing of trees. Patent WO 98/54949 (1998)
2. Lastunen, P.: Harvester unit. Patent WO 93/19909 (1993)
3. Ketonen, L.: Tree trunk feed mechanism. Patent SE 455283 (1988)
4. SP MASKINER Web site:
http://www.spmaskiner.se
5. Gogu, G.: Structural Synthesis of Parallel Robots. Part 1: Methodology. Springer, Dordrecht (2008)