1. Vladim�r ?erm�k,Zem? a jej� tepeln� historie, Academica. Czechoslovak Academy of Sciences, Cesta k v?d?n� No. 10 (Prague, 1966), pp. 1?207.
2. Jan Halousek andKarel P?�hoda,A precise thermistor thermometer for use in geothermics, Geofysik�ln� sborn�k of the Czechoslovak Academy of SciencesXV (1967), 321?335.
3. Catalogue by Atlas Copco ABEM, AB, Fack, S-10110 Stockholm 1, Sweden, Thermoprobe UGF-GTI for Accurate Temperature Measurements in Shallow Drillholes.
4. Lockwood Survey Corporation Limited, Toronto, Canada: Airborne Magnetometer, Scintillation Counter, Dual Frequency Electromagnetometer Survey of a Part of the Asswan Region, United Arab Republic. Unpublished report for the United Nations Development Programme Special Fund in the UAR (Toronto, 1968).
5. Catalogue by Crone Geophysics Limited, 979 Lakeshore Road E., Port Credit, Ontario, Canada:RADEM.