Florence Nightingale, Michael D. Calabria, Janet A. Macrae (1994). “Suggestions for Thought by Florence Nightingale: Selections and Commentaries”, p.13, University of Pennsylvania Press
Florence Nightingale, Michael D. Calabria, Janet A. Macrae (1994). “Suggestions for Thought by Florence Nightingale: Selections and Commentaries”, p.13, University of Pennsylvania Press