1. Spitzer, N. C. A. Rev. Neurosci. 2, 363–397 (1979).
2. Spitzer, N. C. Trends Neurosci. 4, 169–172 (1981).
3. Noden, D. M. in 4th Symp. on Oral Sensation and Perception: Development in the Fetus and Infant (ed. Bosma, J.) 9–36 (US Dept HEW, Bethesda, 1973).
4. Narayanan, C. H. & Narayanan, Y. J. Embryol. exp. Morph. 47, 137–148 (1978).
5. Ziller, C., Le Douarin, N. M. & Brazeau, P. C.r. hebd. Seanc. Acad. Sci., Paris 292, 1215–1219 (1981).