1. Air-Liquide, 2006. Physical data of gasses. Available from: http://www.airliquide.com/.
2. Alvarez, H., 1990. Energiteknik (Energy Technology), 91-44-31471-X. Studentlitteratur, Lund, Sweden, pp. 1294.
3. Aerogel and krypton insulated evacuated flat-plate collector for process heat production;Beikircher;Solar Energy,1996
4. High efficiency evacuated flat-plate solar collector for process steam production;Benz;Solar Energy,1999
5. A non-linear flat-plate collector model;Cooper;Solar Energy,1981