PROCEEDINGS OF OPEN MEETINGS OF WORKING GROUPS ON PHYSICAL SCIENCES OF THE 17TH PLENARY MEETING- COSPAR- COMMITTEE ON SPACE RESEARCH.

---

PROCEEDINGS OF OPEN MEETINGS OF WORKING GROUPS ON PHYSICAL SCIENCES OF THE 15TH PLENARY MEETING OF COSPAR COMMITTEE ON SPACE RESEARCH- 2 VOLS.

---

Space Research XV

---

Space research

---

Space Research

---

PAPERS PRESENTED AT OPEN MEETINGS OF WORKING GROUPS ON PHYSICAL SCIENCES OF THE 18TH PLENARY MEETING OF COSPAR- COMMITTEE ON SPACE RESEARCH- BULGARIAN ACADEMY OF SCIENCES.

---

Space Research

---

Space Research

---

Proceedings of Open Meetings of Working Groups on Physical Sciences of the Eighteenth [18.] Plenary Meeting of COSPAR, Varna, 29 May-7 June 1975 and COSPAR Symposium and Workshop on Results from Coordinated Upper Atmosphere Measurement Programs, Varna, 29-31 May 1975

---

Space Research XIII

---