Cite

    Mario Bruschi and Francesco Calogero. “A convenient expression of the time-derivative, of arbitrary order k, of the zero zn(t) of a time-dependent polynomial pN(z;t) of arbitrary degree N in z, and solvable dynamical systems.” Journal of nonlinear mathematical physics, vol. 23, no. 4, 2016, pp. 474–485. http://access.bl.uk/ark:/81055/vdc_100036752723.0x000005