Question: What are the years employed shown for Mathematics & Prefect Master?
SQL: SELECT "Employed" FROM "2-1839872-3" WHERE "Position held" = 'Mathematics & Prefect Master';

Question: What citation is shown for the employed years of 1970–1996?
SQL: SELECT "Citation" FROM "2-1839872-3" WHERE "Employed" = '1970–1996';

Question: What is the name of the person employed 1970–2005?
SQL: SELECT "Name" FROM "2-1839872-3" WHERE "Employed" = '1970–2005';