Mousa, K.M. , Al-saady, F.A.A. and Mahmood, M.E. 2011. NICKEL RECOVERY FROM RESIDUE OF HEAVY OIL USING NITRIC ACID. Journal of Petroleum Research and Studies. 2, 2 (Jul. 2011), 87-96. DOI:https://doi.org/10.52716/jprs.v2i2.43.