An Oorspronkelijke Aanwijzende Tafel or Original Indicator Table is a ledger of the cadastral administration. It was created in 1832 to show the owners of the plots at that time, when the cadastral administration was introduced. It is organized by municipality and section, and lists all the property owners in that section, or order of plot number. It is commonly abbrevated as OAT.
See Cadastre – Original Indicator Table for more information about this source and how to use it.