1. Davis, T. & Merton, P. A. J. Physiol., Lond. 140, 25P–27P (1957).
2. Miller, E. F. US Naval School of Aviation Medicine Research, Report no. 75, 1–32 (1962).
3. Colenbrander, A. Ophthalmologia 146, 309–313 (1963).
4. Belcher, S. J. Br. J. physiol. Opt. 2, 1–6 (1964).
5. Petrov, A. P. & Zenkin, G. M. Vision Res. 13, 2465–2477 (1973).