Book  (1936)  Page(s) 222.  
 
Dückhardt, Maria (tea) Ketten 1897; Mme. Bravy X Adam; porcelain-white, center reddish reflexes, large, double, fragrance 5/10, floriferous, growth 7/10.

Magazine  (15 Jul 1911)  Page(s) 338.  
 
The Parentage of Roses.
The following list of the world's Roses and their parentage has been compiled by Mr. Robert Daniel, 38 Russell Road. Fishponds, Bristol, and by his kind permission we are enabled to publish it...
Maria Duckhardt... Tea, Ketten, 1897, Mme. Bravy X Adams

Book  (1902)  Page(s) 79.  
 
Thé. 1831. Maria Duckhardt (Ketten 1897), blanc et rouge

Book  (1899)  Page(s) 124.  
 
Maria Duckhardt, thé, Ketten, 1897, blanc centre rouge