Book  (1985)  Page(s) 163.  
 
....in May 1962 we began our career as hybridists...It was in 1964 that we saw the results in the open air, and began to select our first introductions....The most popular, because more conventional, were helped by a fortunate thought in naming them in association with one another. 'King Arthur', 'Guinevere', 'Sir Lancelot' and 'Merlin'. We introduced them in 1967, five years from the time of pollination...

Book  (1972)  Page(s) 220.  
 
Harkness advertisement. Raisers' eye View. 'Merlin; varies from good to disappointing according to weather.

Magazine  (Dec 1970)  Page(s) 4. trimester, p. 47.  
 
Palmares des principaux Concours Européens...Baden-Baden...Floribundas...
Certificat de Mérite: Merlin (Harkness)