This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Knoke. This is taken from the Center for Disease Control's paper Hospitalizations for Unexplained Illnesses among Veterans of the Persian Gulf War by James Knoke and Gregory Gray Naval Health Research Center San Diego California USA cdc gov htm graph PDUSGov original upload log page en Knoke DarwinX bytes no Summary This