1. Althytude Website; www.althytude.info; www.althytude.info/Documents/Safety_Dunkerque.pdf
2. Aral AG, http://www.aral.de
3. Arianespace, http://www.arianespace.com/site/index.html
4. BASF Formaldehydanlage Ludwigshafen, http://www.inorganics.basf.com
5. Bengt Ridell: Malmö hydrogen project. Grontmij AB, Sweden, http://www.risoe.dk/rispubl/SYS/syspdf/energconf05/session3_ridell.pdf