Laura Sydell: DIY Tractor Repair Runs Afoul Of Copyright Law. npr.com, 17. August 2015, abgerufen am 31. August 2015 (englisch): „And the little computer screen lets him know when something is wrong. Unfortunately, Alford isn’t allowed to fix it. John Deere has a digital lock on the software that runs his tractor. And it won’t give him the key.[…] The company went on to say that unqualified individuals could endanger customer safety.“
