Book  (1936)  Page(s) 382.  
 
Keller, Martha (Pol) Walter 1912; porcelain-white, center yellowish white, edges lilac-pink, medium-size, very double, loose clusters, long stems, growth 6/10, dense, Sangerhausen

Magazine  (1914)  Page(s) 291.  
 
Martha Keller, descending from Bébé Leroux and Helene Videnz, is a good sort for cutting. She has a very beautiful dark red colouring and is valuable in all respects.

Magazine  (1 Jun 1912)  Page(s) 89.  
 
MARTHE KELLER (Walter Felberg). Polyantha nain. — Fleur moyenne, bien pleine, formant des bouquets dégagés ; blanc porcelaine, centre blanc jaunâtre, passant au rose lilacé vers les bords.