http://www.wisegeek.org/what-are-some-household-uses-of-ammonia.htm (accessed: 1st August, 2013)http://www.npr.org/programs/morning/features/2002/jul/fritzhaber/ (accessed: 1st August, 2013)
http://www.beefproducts.com/Ammonia-EssentialForLife.pdf (accessed: 22 July, 2013)
http://www.beefproducts.com/Ammonia-EssentialForLife.pdf (accessed: 22 July, 2013)