Maida, Patricia D; Spornick, Nicholas B. (1982). Murder she wrote : a study of Agatha Christie's detective fiction. Bowling Green, Ohio: Bowling Green State University Popular Press. ISBN0879722150. OCLC9167004.
Tromans, Nicholas (2011). 'Hope' : the life and times of a Victorian icon. Watts Gallery (Compton, Surrey). Compton: Watts Gallery. ISBN9780956102270. OCLC747085416.