ISBN 0-903505-46-0* Marrow-Stem Kale: Plants For a Future database* PROTAbase on "Brassica oleracea (headed cabbage)"* Detailed nutritional composition of kale: Nutritiondata.com
== External links ==* Marrow-Stem Kale: Plants For a Future database* PROTAbase on "Brassica oleracea (leaf cabbage)"* Detailed nutritional composition of kale: Nutritiondata.com