9 6 6 , ▁he ▁served ▁as ▁chairman ▁of ▁the ▁university ' s ▁history ▁department . ▁ ▁He ▁retired ▁in ▁ 1 9 7 6 . ▁ ▁Selected ▁bibli ography ▁" An ▁important ▁short ▁chron icle ▁of ▁the ▁four teenth ▁century ", ▁By z ant ion ▁ 1 3 ▁( 1 9 3 8 ) ▁" By z ant ium , ▁the ▁West ▁and ▁the ▁origin ▁of ▁the ▁First ▁Cr us ade ", ▁By z ant ion ▁ 1 9 ▁( 1 9 4 9 ) ▁" On ▁the ▁Social ▁Str ucture ▁and ▁Econom ic ▁Organ ization ▁of ▁the ▁By z antine ▁Empire ▁in ▁the ▁Th ir teenth ▁Century ▁and ▁Later ", ▁By z ant inos lav ica ▁ 1 2 ▁( 1 9 5 1 ) ▁" E th nic ▁Ch anges ▁in ▁the ▁By z antine ▁Empire ▁in ▁the ▁Se vent h ▁Century ", ▁D umb art on ▁O aks ▁Pap ers ▁ 1 3 ▁( 1 9 5 9 ) ▁▁ ▁" The ▁Armen ians ▁in ▁the ▁By z antine ▁Empire ", ▁By z ant inos lav ica ▁ 2 2 ▁( 1 9 6 1 ), ▁Re pr . ▁Lis bon , ▁ 1 9 6 3 , ▁London , ▁ 1 9 7 2 ▁" Ob serv ations ▁on ▁the ▁Dem ography ▁of ▁the ▁By z antine ▁Empire ", ▁XIII ▁International ▁Congress ▁of ▁By z antine ▁Studies , ▁ ▁Oxford , ▁ 1 9 6 6 ▁ ▁References ▁ ▁Category : American ▁By z antin ists ▁Category :