The international daffodil register and classified list 2008 /
Kington, Sally.
Royal Horticultural Society (Great Britain)
London : Royal Horticultural Society,
2008.
"Twenty-fourth cumulative list ... published by the Royal Horticultural Society since 1907"--Page 7.
Narcissus (Plants)
Amaryllidaceae.
"The list appears on the web at http://www.rhs.org.uk/plants/registerpages/intro.asp where it is routinely updated with corrections and amendments and annually with details of new registrations"--Page 7.