Book  (Jan 2000)  Page(s) 226.  
 
Eugene Verdier Tree Peony. ex France [no date given]... pink

Article (magazine)  (Jan 1955)  Page(s) 13.  
 
There were also hundreds of lilac pinks, magenta. pinks and plain magentas, most of which were very unattractive. Many closely resembled Banksi. Typical varieties were 'Archduc Ludovico,' 'Athlete,' 'Beaute de Twickel,' 'Jules PirIot,' 'La Ville de St. Denis,' 'Morris,' 'Princess Louise,' 'Reine Amelie,' 'Reine des Fleurs,' 'Triomphe de Vandermaelen,' and 'van Houttei.' All these varieties proved, in Holland and France, easy to propagate in comparison with the later introduced Japanese varieties. Which varieties bearing European names were actually raised from seed in Europe and which were Chinese varieties renamed is not too definitely established.

Article (magazine)  (Jan 1955)  Page(s) 59.  
 
Alphabetical Check List of Tree Peony Names In  Public Collections And/or Available in Nurseries 1954-1955
Chinese, Purple, 'Princess Louise' (Sen. bef. 1889), [Gardens] Whitnal Park Botanical Gardens

Magazine  (Nov 1911)  Page(s) 61.  
 
ADDITIONAL NOTES AND CORRECTIONS TO DESCRIPTIONS IN BULLETIN 278
Eugène Verdier, page 293. Should be described as very erect habit.