Book  (2016)  Page(s) 192.  
 
Mrs. Littleton Dewhurst.....This rose is a white sport of 'Lady Gay'.  The plant growing at Sangerhausen has sported back to the original pink color.  It is not reported as growing anywhere else so that may be the end of 'Mrs. Littleton Dewhurst'. 

Book  (2003)  Page(s) 136.  
 
 'White Dorothy' is also similar to 'Mrs. Littleton Dewhurst' [Pearson, 1911], which is actually a white sport not of 'Dorothy Perkins' but of "Lady Gay'. 

Book  (1936)  Page(s) 208.  
 
Dewhurst, Mrs. Littleton (hybrid wichurana) Pearson 1912; white, type L. Gay

Book  (1934)  
 
Mrs. Littleton Dewhurst (Wich): Flower pure white, double, in large loose trusses. Growth very vigorous. A. Perg. Pil.

Magazine  (Jun 1929)  Page(s) 67.  
 
Mistress Littleton Dewhurst, blanc pur, pleine.

Website/Catalog  (1914)  Page(s) 7.  
 
Hybrid Wichuranas. Mrs. Littleton Dewhurst. White, similar to Lady Gay.

Book  (1914)  Page(s) 55.  
 
A Descriptive Catalogue of Roses.
Mrs. Littleton Dewhurst (wichuraiana), J. R. Pearson & Sons.—White. Sport from "Lady Gay", which see.

Book  (1914)  Page(s) 164.  
 
Directions for Pruning the following Roses which are not in the last edition of the Handbook on Pruning Roses.
Fraulein Octavia Hesse. wich. Instruction 35 and 37
Mme. Portier-Durel. wich. Instruction 35
Mrs. Littleton Dewhurst. wich. Instruction 35 and 37
Mrs. M. H. Walsh. wich. Instruction 35 and 37
The Gem. wich. Instruction 35
Thelma. wich. Instruction 35

Book  (1913)  Page(s) 98.  
 
Wichuraiana Ramblers. By Dr. A. H. Williams, Vice-President N.R.S.
The wichuraiana Ramblers fall naturally into two well defined groups:
II. The Late, composed of those whose main flowering season lies in the month of July. They mostly have a strain of multiflora in their parentage. The trusses are usually very large, consisting often of an immense number of small flowers, which may be either singles or double rosettes.
Late Flowering Double Varieties.
Mrs. Littleton Dewhurst. —A white sport of Lady Gay; is similar in many respects to White Dorothy.

Magazine  (22 Jul 1911)  Page(s) 350.  
 
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...
Mrs. Littleton-Dewhurst... Multiflora Scandens*, Pearson, 1908, Sport Lady Gay

*i.e., Climbing Polyantha