Guillermo, Allan Q., Manuel A. Bajet, Jr., and Dominador F. Tolentino. 2015. “Effectiveness of the Two-in-One Device; Ignition Coil and Spark Plug Testing Instrument”. JPAIR Multidisciplinary Research 20 (1): 83-103. https://doi.org/10.7719/jpair.v20i1.320.