1. Harper, R., Land, D. G., Grifths, N. M. and Bate-Smith, E. C., Brit. J. Psychol., 1968, 59, 231–52.
2. Demole, E., Enggist, P. and Ohloff, G., Helv. Chim. Acta, 1982, 65, 1785–94.
3. Rothe, M. and Thomas, B., Z. Lebensm. Unters. Forsch., 1963, 119, 302–10.
4. Guadagni, D. G., Buttery, R. G. and Harris, J., J. Sci. Fd Agric., 1966, 17, 142–4.
5. Frijters, J. E. R., in Progress in Flavour Research, Ed. D. G. Land and H. E. Nursten, Applied Science Publishers, London, 1979, 47–51.