:invited reviews given for commission 34 (interstellar matter) of the International Astronomical Union, at the sixteenth general assembly of IAU, Grenoble, August 1976
/ edited by Hugo Van Woerden
Dordrecht, Holland ; Boston
: D. Reidel Pub. Co. ; Hingham, Mass. : sold and distributed in the U.S.A., Canada, and Mexico by D. Reidel Pub. Co