PHILOSOPHICAL MAGAZINE LETTERS, vol. 79, no. 12, page. 919 - 924, 1999-12
JOURNAL OF APPLIED PHYSICS, vol. 86, no. 2, page. 902 - 908, 1999-07-15
JOURNAL OF APPLIED PHYSICS, vol. 86, no. 1, page. 306 - 310, 1999-07-01