1. Statistisches Bundesamt. Communication to the press, 26th of June 2000.
2. Ender C. Wind Energy Use in Germany—Status 31.12.2001—DEWI (German Wind Energy Institute), DEWI magazine no. 20, February 2002, p. 13-27.
3. Regulatory and institutional measures by the state to enhance the development of renewable energies: German experiences;Gutermuth;Solar Energy,2000
4. Act on granting priority to renewable energy sources;Deutscher;Solar Energy,2001
5. IBGE (Instituto Brasileiro de Geografia e Estatistica). Censo 2000, Sinopse Preliminar. Brazil, 2001.