Book  (Oct 2001)  Page(s) 328-329.  Includes photo(s).

Book  (Apr 1998)  Page(s) 129.  

Magazine  (28 Jul 1937)  Page(s) 56.  
 
TWENTY BEST LARGE-FLOWERED HYBRIDS OBTAINABLE IN THIS COUNTRY
Prins Hendrik, azure-blue Lanuginosa Type
All bloom on new wood except Belle of Woking and Sir Garnet Wolseley