Elementary set theory : Part 1 & 2 / [by] Kam-tim Leung and Doris Lai-chue Chen. Foreword by Yung-chow Wong. Leung, Kam-tim. Chen, Doris Lai-chue, joint author. Set theory. QA248 .L39 517.521 KAE Includes index. [Hong Kong] ; London : Hong Kong University Press ; Oxford University Press, 1967. 1967. 1964 Text v. ; eng