Donald J. Patterson Lin Liao Krzysztof Gajos Michael Collier Nik Livic Katherine Olson Shiaokai Wang Dieter Fox Henry A. Kautz Opportunity Knocks: A System to Provide Cognitive Assistance with Transportation Services. 433-450 http://dx.doi.org/10.1007/978-3-540-30119-6_26 2004 conf/huc/2004 Ubicomp db/conf/huc/ubicomp2004.html#PattersonLGCLOWFK04