Before revision:  Here we show how  the next generation operator approach for computing reproduction numbers can be used in conjunction with the generalized linear chain trick (GLCT) to find reproduction numbers expressions that apply generally to such families of models of varying dimensions .
After revision:  Here we show how to find general reproduction number expressions for such models families (which vary in their number of state variables) using the next generation operator approach for computing reproduction numbers can be used in conjunction with the generalized linear chain trick (GLCT) to find reproduction numbers expressions that apply generally to such families of models of varying dimensions .