“The Effect of Using a Rocker Arm on the Performance and Efficiency of a 200cc 4 Stroke Motor: Pengaruh Penggunaan Rocker Arm Terhadap Performa dan Efesiensi Motor 4 Stroke 200cc” (2021) Procedia of Engineering and Life Science, 1(1). doi:10.21070/pels.v1i1.804.