1. Harold C. Urey

   • Zdeněk Kopal

   In Memoriam Pages: ii - 135

2. Elimination of the critical terms in a first-order general planetary theory

   • Osman M. Kamel

   OriginalPaper Pages: 137 - 155

3. Negative ions in comets

   • A. Wekhof

   OriginalPaper Pages: 157 - 173

4. Molecular distribution in the comae of H₂O-comets: An analytic model

   • Tetsuo Yamamoto

   OriginalPaper Pages: 175 - 188

5. The lunar orbit revisited, III

   • François Mignard

   OriginalPaper Pages: 189 - 207

6. Lunar craters evolution and meteoroidal flux in pre-mare and post-mare times

   • L. B. Ronca
   • A. T. Basilevsky
   • B. A. Ivanov

   OriginalPaper Pages: 209 - 229

7. Particle motion in the vicinity of the protosun with variable luminosity

   • B. J. Levin
   • A. N. Simonenko

   OriginalPaper Pages: 231 - 243

8. Движение малых частиц в окрестностях протосолнца переменной светимости

   • Б. ю. Левин
   • А. Н. Симоненко

   OriginalPaper Pages: 245 - 258