Book  (Apr 1993)  Page(s) 634.  
 
Werner Dirks Large-flowered Climber, ivory-white, 1937, 'Mrs. Pierre S. duPont' x 'Daisy Hill'; Kordes. Description.

Magazine  (1939)  Page(s) 60.  
 
Werner Dirks Large-flowered climber (W. Kordes...1937)

Book  (1938)  Page(s) 167.  
 
Wilhelm Kordes: Also of Macrantha origin, but with 'Mrs. Pierre S. du Pont' as pollen parent, is my 'Wirner Dirks', wityh big blooms much in the way of 'Mrs. Charles Lamplough', but more ivory, and very strongly scented.