Shape preserving fractional order KNR C1 cubic spline Syed Kirmani, Norhaida binti Mohd Suaib and Muhammad Bilal Riaz Eur. Phys. J. Plus, 134 7 (2019) 319 Published online: 08 July 2019 DOI: 10.1140/epjp/i2019-12704-1