Book  (1940)  Page(s) 16.  
 
Baronesse van Ittersum Rambler. (M. Leenders 1910)... light crimson, shading deeper...

Book  (1936)  Page(s) 365.  
 
van Ittersum, Baronesse (multiflora) M. Leenders 1910; bright scarlet-crimson, base nasturtium-yellow, large, double, floriferous, free-blooming, growth 8/10, climbing, 4-5m. Sangerhausen

Magazine  (Jun 1929)  Page(s) 70.  
 
Baronness von Ittersum, rouge cramoisi feu, hâtif.

Website/Catalog  (1929)  Page(s) 47.  
 
Hardy Climbing Roses
Baroness Van Ittersum. Hybrid Multiflora. (M. Leenders & Co., 1910.) Flowers light crimson, shaded with orange-red, semi-double, rather large; faint perfume. Strong growth, up to 15 feet; hardy and very floriferous.
Very early flowering, continuing about five weeks. Highly regarded by fanciers of hardy climbing Roses.

Website/Catalog  (1923)  Page(s) 15.  
 
Jkvr. D. Baronesse van Ittersum (M. Leenders & Co, 1910). Multiflora. Brilliant scarlet-crimson-red. Magnificent.
[Jonkvrouw = Dame]

Book  (1918)  Page(s) 84.  
 
[From the article "Multiflora Ramblers" by Edward K. Butler, Jamaica Plain, Mass.]
Baroness van Ittersum. (Leenders and Co., 1911.) Described as a brilliant scarlet-crimson on an orange-red ground. This rose is litle known in America as yet, amd my own plant is still too Young for me to describe it from personal Observation, but Mr. A. J. Fish of New Bedford, Mass., who has grown it for a number of years, writes me that he considers it the best red rose of this class yet introduced.
* See Mr. Fish's noes in another article.

Website/Catalog  (1914)  Page(s) 45.  
 
Climbing Section.
Jkvr D. Baronesse van Ittersum (Climbing Polyantha)... Leenders & Co., 1911, very vigorous. Brilliant scarlet crimson, on an orange red ground; flowering profusely and continuously; superb.

Website/Catalog  (1914)  Page(s) 3.  
 
Once-blooming climbers. Baronesse van Ittersum (multiflora) Scarlet-crimson on yellow base. Very vigorous, hardy

Magazine  (1912)  Page(s) 111.  
 
BARONESSE VAN ITTERSUM , issue de Crimson Rambler x Mademoiselle Laurette Messimy (Mult.); Leenders obtenteur

Website/Catalog  (1912)  Page(s) 5.  
 
Novelties for 1912.
Baroness von Ittersum Climbing Polyantha.  Most vigorous and beautiful glossy deep-green foliage, flowering profusely and continuously; colour brilliant scarlet-crimson on an orange-red ground; superb.