Book  (1936)  Page(s) 758.  
 
Wilhelm, Kaiser (HP) Elze 1878; red currant-garnet coloured, shaded reddish violet, very large, double, fine form, few prickles, strongly veined foliage with grey-green reverse, short branches, growth 7/10

Book  (1906)  Page(s) 82.  
 
5.227. Kaiser Wilhelm, Hybride Remontant, Elze 1872 grenat nuancé

Book  (1902)  Page(s) 139.  
 
Groupe L. — Hybrides Remontants (non-classés)
4745. Kaiser Wilhelm... (Elze 1878)... groseille nuancé.