"K. Morita,M. Yano,T. Ono,H. Tanaka,K. Fujii,H. Uekusa,Y. Narumi,K. Kindo","Singlet Ground State and Spin Gap in S=1/2 Kagom? Antiferromagnet Rb<sub>2</sub>Cu<sub>3</sub>SnF<sub>12</sub>",,"J. Phys. Soc. Jpn.",,"Vol. 77",,"pp. 043707 (1-4)",2008,