OPTICS LETTERS, vol. 17, no. 2, page. 157 - 159, 1992-01-15
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, vol. 7, no. 10, page. 2042 - 2047, 1990-10
OPTICS LETTERS, vol. 14, no. 13, page. 665 - 667, 1989-07-01