http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Proceedings of IAU Symposium No. 55, held in Madrid, Spain, May 11-13, 1972
International Astronomical Union/Union Astronomique Internationale, Symposium No. 55 Held in Madrid, Spain, 11-13 May 1972 ; ; 55