Harim, N.A. and Karim, S.A.A. and Othman, M. and Saaban, A. and Ghaffar, A. and Nisar, K.S. and Baleanu, D.  (2020) Positivity preserving interpolation by using rational quartic spline.  AIMS Mathematics, 5 (4).  pp. 3762-3782.  ISSN 24736988