1. Publisher's announcement

   Announcement Pages: iv - iv

2. Growth of planetesimals and clearance of disks around the T-tauri stars

   • K. M. Guseinov

   OriginalPaper Pages: 1 - 6

3. Encke's special perturbation technique associated with the KS regularized variables

   • Mervat El-Sayed Awad

   OriginalPaper Pages: 7 - 20

4. A determination of the parameters of the level surface of lunar gravity

   • Z. Martinec
   • K. Pěč

   OriginalPaper Pages: 21 - 31

5. Velocity dependent coefficient of restitution and the evolution of collisional systems

   • H. Salo
   • J. Lukkari
   • J. Hänninen

   OriginalPaper Pages: 33 - 43

6. The lower atmosphere of Venus after Vega 1 and 2 missions

   • B. Petropoulos
   • P. Telonis

   OriginalPaper Pages: 45 - 60

7. Stability of particulate discs

   • K. A. Hämeen-Anttila
   • J. Hänninen
   • M. Verronen

   OriginalPaper Pages: 61 - 86