On the Complexity of Generating Optimal Plans with Cross Products. - Wolfgang Scheufele; Guido Moerkotte (PODS, 1997)

Efficient Dynamic Programming Algorithms for Ordering Expensive Joins and Selections. - Wolfgang Scheufele; Guido Moerkotte (EDBT, 1998)

Algebraic query optimization in database systems. - Wolfgang Scheufele (1999)

Review - On the Optimal Nesting Order for Computing N-Relational Joins. - Wolfgang Scheufele (ACM SIGMOD Digit. Rev., 2000)