    Sentence 1: What -did. Shrewsbury note  about the plague?    Sentence 2:.In 1984 zoologist Graham  Twigg produced the first major work to)  challenge the bubonic plague theory  directly, and his. doubts ‘about’ the  identity of the Black Death have. been|  taken up by a number of authors,  including Samuel K. Cohn, Jr. (2002),  David Herlihy (1997), and Susan Scott}  and Christopher Duncan (2001).    