Koch, Matthias, Matthew Black, Endao Han, Joshua Shaevitz, and Zemer Gitai. (2022) 2022. “Distinguishes Surfaces by Stiffness Using Retraction of Type IV Pili.”. Proceedings of the National Academy of Sciences of the United States of America 119 (20): e2119434119. doi:10.1073/pnas.2119434119.