Website/Catalog  (1936)  Page(s) 21.  
 
Paeonia sinensis Empereur Nicolas  ....1 piece RM 1.20

Magazine  (Nov 1911)  Page(s) 61.  
 
ADDITIONAL NOTES AND CORRECTIONS TO DESCRIPTIONS IN BULLETIN 278
Empereur Nicolas, page 278. Remarks — There is another " Emperor Nicolas " in the trade, of a dark purple garnet color 4 (165).
 

Website/Catalog  (Aug 1910)  Page(s) 13.  
 
Pivoines herbacées...Variétés nouvelles...Empereur Nicolas (Cr.); fleurs énormes, plaines, amarante éclatant ...2 fr 50

[no longer listed in the 1935 catalogue]

Book  (1907)  Page(s) 38.  
 
Emperor Nicholas. Crousse, 1897. Enormous, broad-petaled flower, with tufted center; brilliant chatoyant or changeable amaranth, with deep purple reflex. Very brilliant.