The spiral structure of our galaxy :  International Astronomical Union Symposium No. 38 held in Basel, Switzerland, August 29-September 4, 1969 / 
Ed. by W. Becker, G. Contopoulos. 
 - Dordrecht, Holland :  D. Reidel Publ. Co.,  1970. 
 - xiii, 478 p. :  ill. 
 - Symposium (International Astronomical Union)  No. 38 .
<br/><br/><label>Subjects--Topical Terms: </label><br/>Milky Way--Congresses<br/>Spiral galaxies--Congresses