Patent held by Margareth E. Knight Public domain photograph related to motor parts, engines, free to use, no copyright restrictions image - Picryl description
Patent held by Margareth E. Knight
Patent held by Margareth E. Knight Public domain photograph of electrical equipment, power lines, engine, free to use, no copyright restrictions image - Picryl description
Patent held by Margareth E. Knight Public domain photograph of building in Boston, Massachusetts, free to use, no copyright restrictions image - Picryl description
Patent held by Margareth E. Knight Public domain photograph of jet aircraft, free to use, no copyright restrictions image - Picryl description