TETRAHEDRON LETTERS, vol. 41, no. 51, page. 10055 - 10060, 2000-12-16
TETRAHEDRON LETTERS, vol. 41, no. 31, page. 5917 - 5921, 2000-07-29
SYNTHETIC COMMUNICATIONS, vol. 30, no. 23, page. 4205 - 4212, 2000-01