For a given real number $c>0$ define functions $\left(\psi_{k,c}(\cdot)\right)_{k\ge0}$, as an eigenfunctions of the Sturm-Liouville operators $L_c$ defined $$ L_c(\psi)=(1-x^2)\frac{d^2\psi}{dx^2}-2x \frac{d\psi}{dx}-c^2x^2\psi $$ ( in fact, $\psi_{k,c}^{(n)}$ is called the prolate spheroidal wave function).

I would like to find the $n$-th derivative of the prolate spheroidal function $\psi_{k,c}^{(n)}(x)$ .

Any referense r ideas will be very helpful.

Thank you very much.