Book  (Jan 2000)  Page(s) 225.  
 
Yellow King (via Harding) Herbaceous Peony. A Japanese pink lactiflora

Website/Catalog  (1960)  Page(s) 11.  
 
Light Pink Japanese Peonies
Yellow King (Unknown) Large flowers with pale pink guard petals and vivid yellow staminodes. A very beautiful flower. Early. $2.00