1. Royal Netherlands Meteoro-logical Institute and Radio Services of Netherlands P.T.T. Ionospheric data during the period June 25 to July 6, 1954 in connection with the eclipse of June 30, 1954, at DeBilt.
2. Landmark, B., Lied, F. and Skribeland, S.Geofysiske Publikasjoner, 1956,19(8), p. 5.
3. Minnis, CM.Jour. Atmos. Terres. Phys., 1956,9, 201.
4. Becker, W.Solar Eclipses and the Ionosphere (Pergamon Press, London), 1956, p. 36.
5. Booker, H. G. and Seaton, S. L.Phys. Rev., 1940,57, 87.