石盤
↑ "Standard Sizes of Blackboard Slate", U.S Department of Commerce: National Bureau of Standards (1966), 3.
↑ Peter Davies, "Writing Slates and Schooling", Australasian Historical Archaeology, Vol. 23 (2005), 63-64.
↑ Davies, 63.
↑ Davies, 64-65 .
↑ Pierport, 11-13.