Intel 4004 microprocessor oral history panel (2007)
computerhistory.org
computerhistory.org
For example these guys : http://www.xnumber.com/xnumber/microprocessor_history.htm Interesting to read in the CHM article that Hal Feeney had worked at GI in LA. He also talks about military uses of MOS in the 60's.
Or this guy : http://firstmicroprocessor.com/documents/ap1-26-97.pdf
Such dedicated devices were exactly what made the 4004 so special, it was used for calculators but could also be used in other ways because it was a true general purpose CPU.