(Webbsida)
Carlson, W.H. & Crankshaw, C.L. 1981: A commercial grower's guide. Producing Impatiens for Profit.
Extension Bulletin E-1580: Michigan Univeristy, Ann Arbor, MI
http://archive.lib.msu.edu/DMC/Ag.%20Ext.%202007-Chelsie/PDF/e1580-1981-print1.pdf