"PEARS, Charles". Who Was Who. A & C Black, an imprint of Bloomsbury Publishing plc, 1920–2008; online edn, Oxford University Press, Dec 2007. Retrieved 5 August 2013.
"pears, charles". who was who. a & c black, an imprint of bloomsbury publishing plc, 1920–2008; online edn, oxford university press, dec 2007. Retrieved 5 august 2013. {{cite web}}: Check date values in: |accessdate= (help)