1. Consultancy for carbon fixation. Wageningen University & Research, Netherlands. http://www.xs4all.nl/~nlvdbeek/report/index.html.
2. Hiram Firmino. Eucalipto vilão ou herói? Nem vilão nem herói. Jornal do Brasil. On-line: http://jbonline.terra.com.br/jb/papel/cadernos/jb_ecologico/2004/11/03/jorjbe20041103006.html.
3. May Peter H. Forest certification in Brazil. In: Symposium forest certification in developing and transitioning societies: social, economic, and ecological effects. Yale School of Forestry and Environmental Studies. New Haven, Connecticut, USA. 10 & 11 June 2004.
4. Suresh S. Fatigue of materials, Chapter 3 – Contact fatigue: sliding, rolling and fretting. p. 435–82.
5. Metals handbook, vol. 10, Failure and prevention, ASM, 8th ed., Wear failure. p. 134–53.