*[[Accounting]] – [[Denise Schmandt-Besserat]] described the first uses of clay tokens and bullae for keeping track of income and expenses. <ref>http://www.utexas.edu/cola/centers/lrc/numerals/dsb/dsb1.html.</ref> | *[[Accounting]] – [[Denise Schmandt-Besserat]] described the first uses of clay tokens and bullae for keeping track of income and expenses. <ref>http://www.utexas.edu/cola/centers/lrc/numerals/dsb/dsb1.html.</ref> |