There are 3 titles associated with this person.

@book{ wphp_25714
  author={Trapp,Joseph},
  year={1729},
  title={A sermon preach'd before the Right Honourable the Lord Mayor and aldermen of the City of London, at the cathedral church of St. Paul, on Friday, January 30. 1729. Being the Fast-Day for the Execrable Murder of King Charles I. By Joseph Trapp, D. D. Minister of Christ-Church and St. Leonard's Foster-Lane, London. Publish'd at the Request of the Lord Mayor, and the Sheriffs.},
  publisher={Lawton Gilliver \& },
  address={London},    }
@book{ wphp_25005
  author={Trapp,Joseph},
  year={1729},
  title={A sermon preach'd before the Right Honourable the Lord Mayor and aldermen of the city of London, at the Cathedral Church of St. Paul, on Friday, January 30. 1729. Being the fast-day for the execrable murder of King Charles I. By Joseph Trapp, D.D. Minister of Christ-Church and St. Leonard's Foster-Lane, London. Publish'd at the request of the Lord Mayor, and the sheriffs.},
  publisher={},
  address={London},    }
@book{ wphp_25509
  author={Trapp,Joseph},
  year={1739},
  title={The tragedy of King Saul. Written by the author of Abra-mule: or, love and empire. The Second Edition.},
  publisher={},
  address={London},    }