1. Landolt-Börnstein, Zahlenwerte und Funktionen, 4 (Springer Verlag, 1955).
2. Haas, C., thesis, Amsterdam (1956). Shultin, A. A., Dokl. Akad. Nauk S.S.S.R., 125, 767 (1959) assigns the bans in NaNO3 to a component of Davydov splitting of the ν2 mode. This assignment is not in agreement with the temperature-dependence of the intensity which he finds.