Website 1-http://inventors.about.com/od/bstartinventors/a/telephone.htm
Website 2-http://bgr.com/2013/12/13/telephone-timeline-a-brief-history-of-the-phone/
Website 3-http://www.knowlarity.com/15-mind-blowing-facts-telephones/
Website 4-https://blog.ringcentral.com/2014/08/5-facts-telephone-never-knew-friday-five/
Website 2-http://bgr.com/2013/12/13/telephone-timeline-a-brief-history-of-the-phone/
Website 3-http://www.knowlarity.com/15-mind-blowing-facts-telephones/
Website 4-https://blog.ringcentral.com/2014/08/5-facts-telephone-never-knew-friday-five/