Validations of Proofs Considered as Texts: Can Undergraduates Tell Whether an Argument Proves a Theorem?

Annie Selden, John Selden, Validations of Proofs Considered as Texts: Can Undergraduates Tell Whether an Argument Proves a Theorem?, Journal for Research in Mathematics Education, Vol. 34, No. 1 (Jan., 2003), pp. 4-36