When we cite Sparsh we prioritize the WinVR paper and then (if space allows) cite the Sparsh code web site:
Ramanahally, P., Gilbert, S., Anagnost, C., Niedzielski, T., &
Velázquez, D.: Creating a Collaborative Multitouch Computer Aided
Design Program. Proc. of WinVR ‘09 (2009).
Sparsh UI: Retrieved September 7, 2008 from:
http://code.google.com/p/sparsh-ui/ (2008)
Just change the formatting to whatever is most appropriate in your field. The WinVR paper gives an overview discussing Sparsh UI as a framework and some example applications built from it.