John Lennon Tribute Week continues as we talk with Keith Elliot Greenberg, author of “December 8, 1980: The Day John Lennon Died” (Backbeat Books).  Greenberg digs deep into that day, chronicling not only what Lennon was doing, but also what the other Beatles did during that day.  In addition, he profiles each person who played a role in that day, from the photographer and journalist who were in his Dakota apartment in the morning, to the producer who was working in the studio in the afternoon, to policemen, doctors and others who were all directly involved.  He also gives an extensive background of Mark David Chapman, who would ultimately murder Lennon outside his apartment.