Ubong, Ini. U., and Charles Obunwo. “Petroleum Hydrocarbon Contamination of Soil at a Commercial Trailer Truck Parking Facility at Alesa Eleme, Rivers State, Nigeria”. RA Journal of Applied Research, vol. 4, no. 03, Mar. 2018, pp. 1482-93, http://rajournals.in/index.php/rajar/article/view/88.