2. Συστήματα συντεταγμένων των αστέρων

3. Rapid diapir growth, a triggering agent of a 6 1/2 magnitude earthquake on october 29, 1966, in Acarnania (Greece)

4. Black holes as sources of gravity waves

5. Effect of radiation on the carrier lifetimes in semiconductors

6. An introduction to metric geometry

7. Atomic frequency standars

8. The nature and applications of statistics

9. The influence of sunspots on rainfalls, thunderstorms and etesians in Athens

10. Formal integrals of hamiltonian systems in resonance and near - resonance cases

11. The theory of the internal strainfor thw Zinc Blende structure

12. The new 48 inch Cassegrain-Coude telescope

13. On certain sets of sequences

14. The Richardson spectrograph for the 25 inch newall refractor

15. Nicolaus Copernicus

16. Simultaneous observation of TEC fromnorth and south hemispheres during the 30th June 1973 solar eclipse

17. Principles and applications of astronautics

18. Quasars

19. The 25-inch Newall refractor of the astronomical station in Pentele (Athens)

20. The applicability of a new integral in the restricted three body problem II