Zulkurniawan, Zulkurniawan, et al. “DESIGN BUILDING OF AUTOMATED FOOTWEAR AUTOMATIC VEHICLES BASED ON MICROCONTROLLER AT89S51”. Jurnal Ecotipe (Electronic, Control, Telecommunication, Information, and Power Engineering), vol. 2, no. 1, Apr. 2015, pp. 26-33, https://doi.org/10.33019/ecotipe.v2i1.57.