There are 5 titles associated with this firm.

@book{ wphp_14
  author={Hill,Isabel},
  year={1820},
  title={The Poet's Child. A Tragedy, in Five Acts},
  publisher={John Warren},
  address={London},    }
@book{ wphp_14995
  author={Holderness,Mary},
  year={1821},
  title={Notes Relating to the Manners and Customs of the Crim Tatars; Written during a Four Years’ Residence among that People. With Plates. By Mary Holderness.},
  publisher={John Warren \& },
  address={London},    }
@book{ wphp_12291
  author={Francis,Miss},
  year={1821},
  title={Santa Maura: Marion; and Other Poems. By Miss Francis.},
  publisher={John Warren},
  address={London},    }
@book{ wphp_95
  author={Landon,Letitia Elizabeth},
  year={1821},
  title={The Fate of Adelaide, A Swiss Romantic Tale; and Other Poems: By Letitia Elizabeth Landon.},
  publisher={John Warren \& },
  address={London},    }
@book{ wphp_1116
  author={Hill,Isabel},
  year={1822},
  title={Constance. A Tale. By Isabel Hill, author of 'The Poet's Child,' a tragedy.},
  publisher={John Warren \& },
  address={London},    }