Lawvere, F. W., & Landsburg, S. E. (1975). Variable sets etendu: Variable structure in topoi. Dept. of Mathematics, University of Chicago.
Citazione stile Chigago Style (17a edizione)Lawvere, F. W., e Steven E. Landsburg. Variable Sets Etendu: Variable Structure in Topoi. [Chicago]: Dept. of Mathematics, University of Chicago, 1975.
Citatione MLA (8a ed.)Lawvere, F. W., e Steven E. Landsburg. Variable Sets Etendu: Variable Structure in Topoi. Dept. of Mathematics, University of Chicago, 1975.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.