1. Grand, Y. Le (trans. R. W. G. Hunt, J. W. T. Walsh and F. R. W. Hunt), Light, Colour and Vision, 2nd ed., 1968, Chapman and Hall, London.
2. Kierstead, S. P., Natural Dyes, 1950, Bruce, Humphries, Boston, USA;
3. E. Mairet, Vegetable Dyes, 1946, Faberand Faber, London;
4. V. Thurstan, The Use of Vegetable Dyes, 1964, Dryad Press, Leicester.
5. Colour Index, 2nd ed., 1956, Supplement, 1963, The Society of Dyers and Colourists, Bradford; The American Association of Textile Chemists and Colorists, Lowell, Mass., USA.