Book  (Jan 2000)  Page(s) 227, 228.  
 
Page 227: Flower Rivalry. See 'Hanakisoi'.
Page 228: Hanakisoi Tree Peony. ex Japan 1926. Also sold as 'Flower Rivalry'... pink

Book  (Jan 2000)  Page(s) 228.  
 
Hana Kisoi. See 'Hanakisoi'.

Book  (Jan 1999)  Page(s) 60.  Includes photo(s).
 
The tree peony Hana Kisoi reached Europe and the USA from Japan in 1926.

Article (magazine)  (Jan 1955)  Page(s) 57.  
 
Alphabetical Check List of Tree Peony Names In  Public Collections And/or Available in Nurseries 1954-1955
Japanese, Pink, 'Hana-kisoi' (Floral Rivalry) (Jap. bef. 1929), [Gardens] Scott Foundation, Whitnal Park Botanical Gardens, [Nurseries] William Gratwick, Oberlin Peony Gardens

Magazine  (1953)  Page(s) 216.  
 
Hana Kisoi (Floral Rivalry)

Website/Catalog  (1941)  Page(s) [3].  
 
Tree Peonies
Hanakisoi (Contest of Flowers). Enormous; double; deep cherry; waved petals. Tall growth...$20 00

Website/Catalog  (1939)  Page(s) [1].  
 
Tree Peonies (Pæonia arborea)
Japanese Tree Peonies 
English translation in parentheses
38. Hanakisoi (Contest of flowers). Deep cherry; waved petals; enormous size bloom. Exceptionally tall grower. Free bloomer... $20.00