By Guild of One Name Studies, Marker, I.J., Warth, K.E.
By Feinson, Roy
By Spence, Hilary, Chapman, Carole
By Todd, Loreto
By Martin-Doyle, Katie
By Drewett, Richard, Redhead, Mark
By Mark D. Herber
By Hibbert, Christopher
By Pearson, John
By John P. Colletta, John P. Coletta, John Philip Colletta
By National Portrait Gallery
By John Van der Kiste
By Barbara Boyle Torrey, Clara Myrick Green, James Fisher, Tanya Gaskins Hardy, Maurice Jackson
By Matthew L. Helm, April Leigh Helm
By Pauline A. Saul
By Friedrich Wilhelm Nietzsche, Thomas Common
By Brian Hoey
By William Shawcross
By Bella Bathurst
By Peter Summers, John E. Titteron
By Robert K. Massie
By W.G. Crampton
By Patrick Cockburn
By Philip Riden
By W.H. Howe
By Francis Moffat of that Ilk
By Leslie Gilbert Pine