$a Planetary atmospheres : International Astronomical Union Symposium No. 40 held in Marfa, Texas, U.S.A., October 26-31, 1969 / ed. by Carl Sagan, Tobias C. Owen, Harlan J. Smith. - Dordrecht, 1971. $b (Department of Astronomy, University of Texas at Austin, Tex., U.S.A.)