M. Arifhakim Azizan, N. Azlina Mohd Salleh, M. Hussain Ismail, and V. David Natarajan, “Fabrication of Functionally Graded Open-cell Aluminium Foam Using Graded NaCl in Infiltration Casting”, IJET, vol. 7, no. 4.18, pp. 171–175, Nov. 2018, doi: 10.14419/ijet.v7i4.18.21897.