1. Brückner E and Bujakowsky W 1936Forstarchiv 12 121
2. Chatelian A and Weeks R A 1970J. Chem. Phys. 52 5682
3. Hieltzes D 1937Landbouwkund Tijdschr 49 844
4. Use Ness and Kiel V 1958 Kaliu. Steinsalz Bd2 Heft 7
5. Jain V K and Venkateswarlu P 1979J. Phys. C12 865