1. Du Bois: Arch. int. Med. 17, 1916: 863.
2. Boothby-Berkson-Dunn: Amer. J. Physiol. 116, 1936: 468.
3. Bowes-Church: Food Values of Portions commonly used. Philadelphia, College Office Press 1951.
4. Daniel-Munsell: Vitamin content of foods. Washington 1933.
5. Droese-Bramsel: Vitamintabellen der gebräuchlichsten Nahrungsmittel. Leipzig 1941.