Rate of polymerization for copolymers with two monomers

I've found in textbooks that for a chain growth homopolymerization the rate of polymerization $r\_\mathrm{p}$ is


$$r\_\mathrm{p} = k\_\mathrm{p}\sqrt{\frac{f\_\mathrm{kd}}{k\_\mathrm{t}}}c\_\ce{A}^ac\_\ce{B}^b,$$


where $k\_\mathrm{p}$ is the rate constant of propagation; $k\_\mathrm{t}$ is the rate constant of termination; $f\_\mathrm{kd}$ is the constant for chain initiation.


What is the rate equation for chain growth copolymerization $r\_\mathrm{p}$ such as styrene-butadiene rubber (SBR) synthesis? In many polymer textbooks it only shows the [Mayo–Lewis equation](https://en.wikipedia.org/wiki/Mayo%E2%80%93Lewis_equation) which I understand is not the $r\_\mathrm{p}$ equation required for volumes calculations for reactors.


