Mandelbrot and Julia Set

Consider a dynamical system $$z_{n+1}=\frac{\alpha+z_n}{1+z_{n-1}}$$ for $n=0,1,2,\dots$

In other words the system is $$z_{n+1}=f_{\alpha}(z_n,z_{n-1})$$ where $f_{\alpha}$ is defined from $B(z,r)\times B(z,r)$ to $B(z,r)$ as $f_{\alpha}(z,w)=\frac{\alpha+z}{1+w}$. $B(z,r)$ is an open ball in complex plane.

How can we find out the Mandelbrot and Julia sets for this system?