Alfs, M. 2001. Edible & Medicinal Wild Plants of Minnesota & Wisconsin. Pages 276-280. Violet. Old Theology
            Book House, New Brighton, Minnesota, USA.

Bohlin, L.; Claeson, P.; Craik, D. J.; Göransson, U.; Herrmann, A.; Svangård, E.; Trabi, M. 2004. Variations in 
             Cyclotide Expression in Viola Species. Journal of Natural Products 67(5):806-810.

Bown, D. 1995. Encyclopedia of Herbs and Their Uses. Pages 220 & 370. Viola & V. Odorata. Dorling  
             Kindersley Publishing, New York, New York, USA.

Brunt, A.A., Crabtree, K., Dallwitz, M.J., Gibbs, A.J., Watson, L. and Zurcher, E.J. (eds.) (1996). URL
             <http://biology.anu.edu.au/Groups/MES/vide/>.  Accessed 21 April  2008.  

Colgrave, M. L.; Craik, D. J.; Ireland, D. C. 2006. A novel suite of cyclotides from V. odorata: Sequence variation
              and the implications for structure, function and stability. Biochemical Journal 400:1-12.

Franco, O. L.; Pelegrini, P. B.; Quirino, B. F., 2007. Plant cyclotides: An unusual class of defense compounds.
              Peptides (New York) 28 (7):1475-1481.

Gorb, E.; Gorb, S. 2000. Effects of seed aggregation on the removal rates of elaiosome-bearing Chelidonium
              majus and Viola odorata seeds carried by Formica polyctena ants. Ecological Research 15(2):187-192.

Hériteau, J. 1990. The National Arboretum Book of Outstanding Garden Plants. Pages 40 & 71. Viola. The
              Stonesong Press, New York, New York, USA.

Heukels, P. 2000. Wild Flowers of Britain and Europe. Page 1148. Sweet Violet. HarperCollins Publishers,
              Fulham Palace Road, London.

Hylton, W. H. 1974. The Rodale Herb Book. Page 615. Violet. Rodale Press Book Division, Emmaus,
              Pennsylvania, USA.

Mabey, R. 1996. Flora Britannica. Pages 126-130. Violet Family. Chatto & Windus, Random House, London.

Marcussen, T. 2006. Allozymic variation in the widespread and cultivated Viola odorata (Violaceae) in western
               Eurasia Botanical Journal of Linnean Society 151(4):563-571.

Perry, F. 1972. Flowers of the World. Pages 305-307. Violaceae. Crown Publishers, USA.

Stevens, J. 1988. The National Trust Book of Wild Flower Gardening. Page 92. Sweet Violet. The Globe Pequot
                Press, Chester, Connecticut, USA.