Book  (1936)  Page(s) 397.  
 
Lager, Domkapitular Dr. (HT) Lambert 1903; Testout X Princesse de Bassaraba; salmon-pink and carmine, large, double, fragrance 5/10, upright stems, growth 6/10

Website/Catalog  (1929)  Page(s) 15.  
 
Everblooming Roses
The so-called Everblooming Roses include the Hybrid Tea and Pernetiana groups. They do not bloom all the time, but if kept healthy and growing steadily, one crop of flowers succeeds another at brief intervals.
Domkapitular Dr. Lager. Hybrid Tea. (P. Lambert, 1903.) Salmon-pink and carmine blooms, unusually fragrant and freely produced. Plant of good, upright growth, with handsome foliage.
Practically identical in flower and foliage with Betty. If anything, it is a stronger grower and has all of Betty’s good qualities.

Magazine  (27 May 1911)  Page(s) 254.  
 
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...
Domkap. Dr. Lager... Hybrid Tea, Lambert, 1903, Caroline Testout X Princesse de Bassaraba

Website/Catalog  (1907)  Page(s) 201.  
 
Hybrides de thés (remontants) .. Domcapitular Dr. Lager, rose saumoné et carmin.