Book  (2003)  Page(s) 133.  
 
I.X.L.' syn. 'Coolidge' (Coolidge, 1925)

Book  (Apr 1993)  Page(s) 263.  
 
I.X.L.R. Rambler, flowers magenta, 1925, 'Tausendschön' x Veilchenblau'; Coolidge...

Book  (1977)  Page(s) 27.  
 
... in Pasadena [California], Douglas Coolidge, developed the 'IXL' stock for tree roses... just before World War I...

Magazine  (Jul 1950)  Page(s) 3. trimester, p. 70.  
 
[From the article "Les Portes-Greffes du Rosier" by André Leroy, pp. 68-74]
Aucune imprécision non plus en ce qui concerne les porte-greffes dits américains parce qu'ils sont grandement utilisés aux U.S.A. ; le Ragged Robin, qui est le Gloire des Rosomanes ; puis la variété Docteur Huey (Schafter), hybride de Wichuraiana, et enfin le I.X.L., hybride bien déterminé entre les variétés très connues Tausendschon et Veilchenblau. Ces porte-greffes sont surtout utilisés en Californie.

Magazine  (1937)  Page(s) 145.  
 
No reference has been found to the cytology of the American Rose stocks I.X.L., Texas Wax Rose, and Rosa laevigata, in any papers so far seen. Miss Ferguson states of the stock I.X.L. "...It is a seedling of Veilchenblau (the Blue rambler) and was raised by D.W. Coolidge in the Coolidge Rare Plant garden, Pasadena, California. Coolidge states that it is very vigorous and has smooth bark and few prickles. When budded it gives a 'bud break,' in five days, and flowers in twenty-eight days....

Book  (1936)  Page(s) 365.  
 
I.X.L. (multiflora) Coolidge 1925; Tausendschön X Veilchenblau; lilac-violet to magenta, double, globular, cluster-flowered, fragrance 3/10, floriferous, small buds, no prickles, very strong canes, growth 9/10, climbing.

Book  (1934)  
 
IXL - This American stock has not yet been used in England and has not been under my observation. It is a seedling of Veilchenblau (the Blue Rambler) and was raised by D.W. Coolidge in the Coolidge Rare Plant garden, Pasadena, California

Book  (1934)  Page(s) 82.  
 
The stock he refers to was developed as a hybrid between Tausendschön and Veilchenblau by the late D. W. Coolidge, of Pasadena, who christened it "I.X.L."

Book  (1933)  Page(s) 187.  
 
I. X. L. D. W. Coolidge, 1925. Multiflora. Useful only as an understock. Purplish flowers somewhat like Veilchenblau.

Book  (1929)  Page(s) 140.  
 
This article would not be complete without mentioning the new understock originated by the late D. W. Coolidge, of Pasadena. This stock, which he called "I.X.L.," is a cross of Tausendschön X Veilchenblau and is particularly adapted for standards. It makes rapid growth, is thornless and easily...