It was a combination of sources. American Jefferey Taubenberger developed the genetic sequencing technique to figure out the genetic sequence of the Spanish Flu first from preserved samples from the US Armed Forces Pathology Institute. But he wasn't able to figure out the whole sequence just from those samples. It took the exhumation of a preserved from the Alaska permafrost to figure out the rest of it. Then he published the entire genome as well as how to recreate the virus so even YOU can call my 1-800 number and order your own Spanish Flu Chia pet. Call now!