TETRAHEDRON LETTERS, vol. 34, no. 52, page. 8465 - 8468, 1993-12-24
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, vol. 115, no. 16, page. 7472 - 7477, 1993-08-11
TETRAHEDRON LETTERS, vol. 34, no. 10, page. 1609 - 1610, 1993-03-05
TETRAHEDRON, vol. 49, no. 2, page. 293 - 318, 1993-01-08