Establishing key criteria to define and compare models of specialist palliative care: A mixed-methods study using qualitative interviews and Delphi survey. - Firth AM; O'Brien SM; Guo P; Seymour J; Richardson H; Bridges C; Hocaoglu MB; Grande G; Dzingina M; Higginson IJ; Murtagh FE (Palliative medicine, 2019)