Chattopadhyay, Manas K., Celia White Tabor, and Herbert Tabor. "Spermidine but not spermine is essential for hypusine biosynthesis and growth in Saccharomyces cerevisiae: Spermine is converted to spermidine in vivo by the FMS1-amine oxidase." Proceedings of the National Academy of Sciences 100.24 (2003): 13869-13874. Web. 26 June. 2019.