  In the context of survival analysis, Marshall and Olkin (1997) introduced
families of distributions by adding a scalar parameter to a given survival
function, parameterized or not. In that paper, we generalize their approach. We
show how it is possible to add more than a single parameter to a given
distribution. We then introduce very flexible families of distributions for
which we calculate some moments. Notably, we give some tractable expressions of
these moments when the given baseline distribution is Log-logistic. Finally, we
demonstrate how to generate sample from these new families.
