The Mylar Balloon Revisited. - Ivaïlo M. Mladenov; John Oprea (Am. Math. Mon., 2003)

Flat circle bundles, pullbacks, and the circle made discrete. - John Oprea; Daniel Tanré (Int. J. Math. Math. Sci., 2005)

On the geometry of the rotating liquid drop. - Ivaïlo M. Mladenov; John Oprea (Math. Comput. Simul., 2016)

A fundamental group for digital images. - Gregory Lupton; John Oprea; Nicholas A. Scoville (J. Appl. Comput. Topol., 2021)

Homotopy Theory in Digital Topology. - Gregory Lupton; John Oprea; Nicholas A. Scoville (Discret. Comput. Geom., 2022)

Subdivision of Maps of Digital Images. - Gregory Lupton; John Oprea; Nicholas A. Scoville (Discret. Comput. Geom., 2022)