Vehicle repairs
. "Reducing emissions from in-use vehicles: an evaluation of the Phoenix inspection and maintenance program using test results and independent emissions measurements." Environmental Science & Policy 4.6 (2001) 359–376.
. "Evaluating the long-term effectiveness of the Phoenix IM240 program." Environmental Science & Policy 4.6 (2001).
. "Use of remote sensing measurements to evaluate vehicle emission monitoring programs: results from Phoenix, Arizona." Transportation Research Part D 6.2 (2003).