PHYSICAL REVIEW B, vol. 37, no. 10, page. 5966 - 5969, 1988-04-01
PHYSICAL REVIEW B, vol. 36, no. 7, page. 3638 - 3650, 1987-09-01
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, vol. 26, page. 1385 - 1386, 1987-01
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, vol. 26, page. 1423 - 1424, 1987-01
PHYSICAL REVIEW LETTERS, vol. 56, no. 26, page. 2880 - 2880, 1986-06-30
PHYSICAL REVIEW LETTERS, vol. 55, no. 19, page. 2051 - 2054, 1985-01