Book  (Oct 2001)  Page(s) 328.  Includes photo(s).

Website/Catalog  (1912)  Page(s) 78.  
 
Summer and Autumn Clematis.
In bloom from July to October.
These flower upon the wood of the current year's growth, and should therefore be pruned to five or six eyes.  The varieties most suitable for bedding are marked thus* 
*Princess of Wales, deep bluish mauve, with a satiny surface...  1s. 6d.

Book  (1906)  Page(s) 53.  
 
Principal garden varieties of Clematis:
Lanuginosa type. (July to October.)
Princess of Wales... Bluish-mauve.

Magazine  (24 Nov 1900)  Page(s) 90.  
 
Die Firma Simon Louis frères, Plantières bei Metz, hatte Neuheiten und seltene Sorten ausgestellt, die für unsere Landschaftsgärtner von hoher Wichtigkeit sein werden, so Clematis Viticella fl. pl. Lamartine, völlig gefüllt blühend,  Viticella rubra grandiflora, Viticella kermesina und die riesenblumigen Sorten „Princesse of Wales" „Paul Avenel" , "William Kennet'', „Max Leichtlin" u. a.

Translation:
The company Simon Louis frères, Plantières near Metz, had exhibited novelties and rare varieties, which will be of great importance to our landscape gardeners, such as Clematis Viticella fl. pl. Lamartine, completely double flowering, Viticella rubra grandiflora, Viticella kermesina and the giant-flowered varieties “Princesse of Wales”, “Paul Avenel”, “William Kennet”, “Max Leichtlin” and others.

Magazine  (17 Aug 1895)  Page(s) 117.  
 
Clematis Princess of Wales. — This is a fine variety.  The colour is bright lavender and its blooms are each about 6 inches across.  I saw a specimen in flower a short time back which had been planted against a house four years, and it had upwards of a hundred blooms fully out at one time.  The showy character of such a plant may easily be realised.

Magazine  (28 Oct 1882)  Page(s) 414.  
 
The Clematis in the Midlands.
...The sorts I have most successfully grown are the following, and the mode of cultivation that recommended by Mr. Jackman.  Lanuginosa type: Gem, lanuginosa, lanuginosa candida, Otto Frœbel, Princess of Wales, purpurea elegans, Gloire de St. Julienne.

Magazine  (1877)  Page(s) 270.  
 
Clematis Princess of Wales (Jackman), s. des lanuginos; bleu mauve.

Magazine  (29 May 1875)  Page(s) 684.  
 
MESSRS. JACKMAN'S CLEMATISES.
Messrs. Jackman & Son's popular exhibition at Regent's Park has now been brought to a close, and we may fittingly call attention at its termination to some of the charming novelties which it has been the means of introducing to our notice. [...] Several fine novelties of the lanuginosa set were added during the later days of the show, and among them the following:
Princess of Wales, with very broad sepals, which are slightly recurved, giving the flower a distinct outline.  In this and several other varieties of the same cross the sepals are so broad that the four inner ones meet, so as to produce of themselves a close flower.  The colour in this case is a deep, smooth-looking satiny mauve, and the whole character of the plant is regal.

Magazine  (1875)  Page(s) 183.  
 
Note sur la Clématite et ses variétés.
Par M. Delépine, aîné, secrétaire.  Mai 1875.
Clématites de pleine terre.
Clematis Princess of Wales (Jackman), semis des lanuginosa; bleu mauve.