A model of the terrestrial ionosphere in the altitude interval 50–4000 km II. Molecular ions (N2 +, NO+, O2 +) and electron density W. Köhnlein OriginalPaper Pages: 109 - 163
On the short term variations of solar activity during solar cycle 21 Tamer Ataç OriginalPaper Pages: 165 - 170
Efficient algorithms for the earth's gravitational potential and its partial derivatives for satellite prediction Mohamed Adel SharafMervat El-Sayed AwadMona A. Banaja OriginalPaper Pages: 171 - 192
Photographic observations of the cloud in the neighbourhood of libration point L 5 of the Earth-Moon system Maciej Winiarski OriginalPaper Pages: 193 - 215