40.　Submillimeter wave ESR measurements of Ca1-xCuO2 with edge-sharing CuO2 chains
A. Ueda, H. Ohta, S. Okubo, H. Hiroi, M. Okumura and M. Takano
Magn. Reson. 19 (2000) 399-402.

41.　Submillimeter wave ESR measurements of gapless S=1 antiferromagnetic bond alternating chain system
H. Ohta, S. Okubo, S. Kimura, H. Kikuchi and H. Nagasawa
Physica B 284-288 (2000) 1627-1628

42.　High-field magnetization measurement of three-dimensional antiferromagnet Nd2BaNiO5 single crystal
S. Okubo, H. Ohta, T. Tanaka, T. Yokoo, J. Akimitsu
Physica B 284-288 (2000) 1475-1476.

43.　Metamagnetic Transitions of R2Cu2O5 Studied by Submillimeter Wave ESR
T. Goto, S. Kimura, S. Okubo, H. Ohta and M. Motokawa
J. Appl. Magnetic Reson. 18 (2000) 463-468.

44.　Submillimeter Wave ESR Measurements of Low-Dimensional Quantum Spin System
H. Ohta, S. Okubo, S. Kimura, T. Tanaka, H. Kikuchi and H. Nagasawa
J. Appl. Magnetic Reson. 18 (2000) 469-474.