Muhammad Taimoor Khan, Wolfgang Schreiner,
"On Formal Specification of Maple Programs"
, in Johan Jeuring, John A. Campbell, Jacques Carette, Gabriel Dos Reis, Petr Sojka, Makarius Wenzel, Volker Sorge: Intelligent Computer Mathematics, Serie Lecture Notes in Artificial Intelligence (LNAI), Vol. 7362, Springer, Berlin/Heidelberg, Seite(n) 442-446, 7-2012, ISBN: 978-3-642-31373-8