**Acknowledgments **

The authors are especially grateful to Robert L. Knighten, Adjunct Professor of Mathematics at Portland State University, for his help in clearing up some of the finer points related to the historical development of integration theory during the second half of the 17th century. We also want to thank the referees of this article for their careful reading of the manuscript and their useful suggestions, thanks to which this work has improved significantly.

**About the Authors**

Jorge López Fernández is Professor of Mathematics at the University of Puerto Rico in Río Piedras, San Juan, Puerto Rico, where his mathematical interests are harmonic analysis and mathematics education.

Omar Hernández Rodríguez is Assistant Professor in the Graduate School of Education at the University of Puerto Rico. His interests include cognitive and meta-cognitive processes in mathematical problem-solving; incorporating new technologies into the teaching of mathematics; professional development of teachers; and theory, design, development, and evaluation of mathematics curriculum.