How would you parenthetically cite an author that appears twice in a works cited page? I would like to cite Wachs. Here is a piece of my works cited:
Wachs, Juan, Helman Stern, Yael Edan, Michael Gillam, Craig Feied, Mark Smith, and Jon Handler. Gestix: A Doctor-Computer Sterile Gesture Interface for Dynamic Environments. Tech. Web. 21 Mar. 2012.
Wachs, Juan, Yu-Ting Li, and Mithun Jacob. "Gestonurse." Gestonurse. Purdue University Industrial Engineering Lab., 2012. Web. 21 Mar. 2012.
Assuming that I would like to parenthetically cite the second source, how would I go about doing this to differentiate from the first source?