> **Possible Duplicate:**  
> [Derivate Bessel Function with respect to order](https://mathoverflow.net/questions/4019/derivate-bessel-function-with-respect-to-order)  


Dear colleagues, 
I have a question about the modified Bessel function of the second kind, $I_\nu(x)$ and $K_\nu(x)$.  I want to know if there is any result on the derivatives with respect to the parameter $\nu$ of $I_\nu(x)$ and $K_\nu(x)$. That is I want to know where I can find some reference about $\partial_\nu I_\nu (x)$ and $\partial_\nu K_\nu (x)$.

Thank you in advance!