Book  (Jan 2000)  Page(s) 236.  
 
Gold Sovereign Hybrid Tree Peony. (Saunders 1949). A semi-double gold hybrid

Magazine  (Sep 1977)  Page(s) 20-21.  
 
"Botanical Descriptions of 40 Saunders Lutea Hybrids" by Dr. David Reath and Silvia Saunders
...These descriptions aim to provide the nurseryman and the average gardener with a means of determining the differences between the hybrids, many of which are very similar indeed...
Gold Sovereign—Semi-double medium-size blooms, clear yellow. Flares small and dark; heart otherwise all gold-and-cream. Filaments fine, uneven lengths. Anthers "naked". Stigmas cream; sheath cream.

Website/Catalog  (1960)  Page(s) 15.  
 
Tree Peony Hybrids or Lutea Hybrids
Crosses of the Japanese Tree Peony (P. moutan or suffruticosa) onto P. lutea or P. Delavayi. These bloom through the first half of June, sometimes longer. [...]
Because these hybrids fall rather naturally into a few large color groups, I have listed them by color, with the suggestion that when ordering, you either specify a group number only, or allow me some latitude in substituting. [...]
2. The "Golden Hind" Group.
Yellow, clear or almost clear. Generally semi- or fully double.
Gold Sovereign  Exquisite bright gold flat rosette with golden heart. High-held flowers.

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...
'Gold Sovereign,' (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, 'Gold Sovereign' (Saund. 1950)

Magazine  (Mar 1954)  Page(s) 22.  
 
Hybrid Tree Peonies
...By far the most important work with these hybrids has been done by Prof. A. P. Saunders and his originations now number about 80. Their color range is truly remarkable. [...]
The list of hybrid tree peonies following is up to date as far as we could make it.
Originations of A. P. Saunders, Clinton, N.Y.
Hybrids of suggruticosa, lutea and Delavayi.
Gold Sovereign, Double, bright golden. 1949.

Website/Catalog  (1949)  Page(s) [8].  
 
Hybrids Between Chinese Tree Peonies and P. Lutea or P. Delavayi
Gold Sovereign. (1949) Exquisite bright golden, flat double rosette. Very good and distinct.