Naranjilla—Julia Morton, Fruits of Warm Climates
The Naranjilla, the Cocona and Their Hybrid—Charles B. Heiser
"New" Solanums—Charles Heiser and Gregory Anderson
Magness, J.R., G.M. Markle, C.C. Compton. 1971. Food and feed crops of the United States.
Naranjilla can be found in Lost Crops of the Incas from National Academy Press