Tropical Fish Magazine (TFH) in the March 1961 issue, has a short article by Thelma Hobson
Simpson titled "How I Developed the Simpson Swordtail".
Innes "Exotic Aquarium Fishes" (most editions) says of these "Early in 1960
what is now commonly referred to as the Simpson Hi Fin Swordtail was
introduced to the aquarium hobby. The mutation was developed by Mr.
and Mrs Thomas Simpson of Gardena, California."
Robert Ellerman recounts this history of the hifin sword that Mrs. Simpson bred.