1. Department of Forest Biomaterials Science and Engineering, North Carolina State University, Raleigh, NC 27695-8005
2. Lab. LMSSI, Universidad de Los Andes, Mérida, Venezuela
3. Lab. Petroquímica y Surfactantes, LUZ, Maracaibo, Venezuela
4. Lab. FIRP, Universidad de Los Andes, Mérida 5101, Venezuela