Book  (1986)  Page(s) 83.  Includes photo(s).
 
Chinas and their Hybrids. Unermüdliche (1904). A more recent hybrid which has purple-red and white flowers, medium sized and semi-double. A different, pretty and useful variety.

Book  (1976)  Page(s) 177.  
 
location 33, II/11, Unermüdliche (P. Lambert 1904), hybrid china, purple-red, center white, medium-size, semi-double, short

Website/Catalog  (1967)  Page(s) 24.  
 
China Roses and hybrids .... Unermüdliche (P. Lambert, 1904). Carmine to purple-red, semi-double.

Book  (1936)  Page(s) 718.  
 
Unermüdliche (china) Lambert 1904; Ctsse. de Leusse X Testout; carmine to purple-red, center white, medium-size, semi-double, flat, in clusters of 7-30, floriferous, continuous bloom, growth 5/10, short. Sangerhausen

Book  (1936)  Page(s) 184.  
 
Crown = Unermüdliche.

Magazine  (19 Aug 1911)  Page(s) 404.  
 
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...
Unermüddliche... Hybrid Tea, Lambert, 1904, Comtesse de Leusse X Caroline Testout

Book  (1906)  Page(s) 164.  
 
10.554. Unermuedliche, Hybride de Thé, P. Lambert 1904 pourpre centre blanc

Magazine  (9 Nov 1901)  Page(s) 542-543.  
 
Neue und neueste Rosen von Peter Lambert-Trier auf der Gartenbau-Ausstellung in Mainz.....
Es befanden sich noch mehrere benannte und unbenannte Polyantha-Sämlinge zwischen den Lambert'schen Rosen, wie z. B. Philippine Lambert mit sehr hübschen Knospen und schönen rosafarbenen, regelmässig gebauten, langstieligen Blumen. Eine Unermüdliche benannte Bengal-Hybride in bordeauxroter Färbung mit sehr grossen Blütenständen dürfte eine gute Gruppensorte abgeben.

Translation:
New and newest roses from Peter Lambert-Trier at the horticultural exhibition in Mainz... There were several named and unnamed polyantha seedlings among the Lambert roses, such as: Philippine Lambert with very pretty buds and beautiful pink, regular, long-stemmed flowers. A Hybrid China named Unermüdliche in a burgundy colour with very large inflorescences should make a good group variety.