context: In addressing the question of who invented the incandescent lamp, historians Robert Friedel and Paul Israel list 22 inventors of incandescent lamps prior to Joseph Swan and Thomas Edison. They conclude that Edison's version was able to outstrip the others because of a combination of three factors: an effective incandescent material, a higher vacuum than others were able to achieve (by use of the Sprengel pump) and a high resistance that made power distribution from a centralized source economically viable.
question: ఎడిసన్ యొక్క దీపం ఇతర ప్రారంభ వెర్షన్ల కంటే ప్రయోజనాలను గురించి ఏ చరిత్రకారులు రాశారు?
answers: Robert Friedel and Paul Israel