Randolph Y. Wang Sumeet Sobti Nitin Garg Elisha Ziskind Junwen Lai Arvind Krishnamurthy Turning the postal system into a generic digital communication mechanism. 159-166 2004 conf/sigcomm/2004 SIGCOMM http://doi.acm.org/10.1145/1015467.1015485 db/conf/sigcomm/sigcomm2004.html#WangSGZLK04