Calling all archive-holders and reference-sleuths!

According to this citation, SftP activists associated w/ Science for Vietnam published "The Big Gun is the Rain": a "report on the use and potential for geophysical warfare by the US" in Vietnam. As SftP approaches its publication of a collection of essays on geoengineering, such a report might make for a great candidate for digitization and re-publication. 

Do you know where we might find a copy? 

Thanks for your help!
Chris