Watson, S. J., Bishop, G., Drummond, J. C., Gillam, A. E., & Heilbron, I. M. (1934). The relation of the colour and vitamin A content of butter to the nature of the ration fed: The influence of the ration on the yellow colour of the butter. II. The carotenoid and vitamin A contents of the butter.

Watson, Stephen John, Gerald Bishop, Jack Cecil Drummond, Albert Edward Gillam, and Isidor Morris Heilbron. The Relation of the Colour and Vitamin A Content of Butter to the Nature of the Ration Fed: The Influence of the Ration On the Yellow Colour of the Butter. II. The Carotenoid and Vitamin A Contents of the Butter. 1934.

Watson, Stephen John, et al. The Relation of the Colour and Vitamin A Content of Butter to the Nature of the Ration Fed: The Influence of the Ration On the Yellow Colour of the Butter. II. The Carotenoid and Vitamin A Contents of the Butter. 1934.