James Fogarty Jennifer Lai Jim Christensen Presence versus availability: the design and evaluation of a context-aware communication client. 299-317 2004 61 Int. J. Hum.-Comput. Stud. 3 http://dx.doi.org/10.1016/j.ijhcs.2003.12.016 db/journals/ijmms/ijmms61.html#FogartyLC04