Article (magazine)  (Jan 1955)  Page(s) 25.  
 
Varieties Raised in America. All by Professor Saunders...
The "Golden Hind Group." Yellow, clear or almost clear , generally semi- or fully double...
'Hyperion,' (1948-1950)

Article (magazine)  (Jan 1955)  Page(s) 57.  
 
Alphabetical Check List of Tree Peony Names In  Public Collections And/or Available in Nurseries 1954-1955
Lutea hybrid, Yellow, 'Hyperion' (Saund. 1948-1950), [Gardens] scott Foundation

Book  Page(s) 12.  
 
14919 Hyperion 4 grafts in 1941 in 10.13 & 7
1942 in 10.13 Double Argosy. Quite full. flat. Outer petals almost white. Fine bright center
1944 1 bloom 10.13 Very fine double Argosy. Push.