1. 1. Darwin, C. The Expression of the Emotions in Man and in Animals. London: J. Murray, 1873, pp. 147–177.
2. 2. Engel, G. L. Fainting, Physiological and Psychological Considerations. Springfield, III.: Charles C. Thomas, 1950, p. 74.
3. 3. Hertz, J. H., Ed. The Pentateuch. Hebrew Text, English Translation and Commentary. London: Soncino Press, 1938, p. 125.