There are 2 titles associated with this firm.

@book{ wphp_6217
  author={Heron,Mary},
  year={1790},
  title={The conflict. A sentimental tale in a series of letters.},
  publisher={},
  address={Newcastle upon Tyne},    }
@book{ wphp_6233
  author={Heron,Mary},
  year={1792},
  title={Odes, &c. on various occasions. By Mary Heron, Authoress Of The Conflict, &c.},
  publisher={},
  address={Newcastle upon Tyne},    }