Lengvenis, P., R. Simutis, V. Vaitkus, and R. Maskeliunas. “Application Of Computer Vision Systems For Passenger Counting In Public Transport”. Elektronika Ir Elektrotechnika, vol. 19, no. 3, Feb. 2013, pp. 69-72, doi:10.5755/j01.eee.19.3.1232.