Qi Duan K. Djidjeli W. G. Price Edward H. Twizell Constrained control and approximation properties of a rational interpolating curve. 181-194 2003 152 Inf. Sci. http://dx.doi.org/10.1016/S0020-0255(02)00409-7 db/journals/isci/isci152.html#DuanDPT03