Who founded Spectrum Engineering and what is the ownership composition?

Spectrum Engineering was originally founded by Patricia K. Bowles and David L. Bowles, P.E. with each having 50% stock ownership.  In January of 2004, David and Patricia sold the company to their two eldest sons, Scott D. Bowles, P.E. and Tracy L. Bowles.  Trace and Scott requested that David and Patricia remain as stockholders out of respect for their many years of service.  Currently, Trace and Scott each own 45% with David and Patricia holding 5% each.