Forgive me if Henry or someone else has posted this link before.
BREEDING FOR RESISTANCE TO THE BLACK SPOT (Diplocarpon rosae WOLF) DISEASE IN ROSE 2: A SEARCH FOR HIGHLY RESISTANT ROSE SPECIES IN SOUTHERN JAPAN
BOONTIANG, K.1* and YAMAGUCHI S.
Journal of Breeding and Genetics 34(2) 115-119, 2002