If you think about the two-dimensional efficiency/robustness space you can pretty easily see how it's isomorphic to the return/volatility space by way of simple transformations. If yourself to be convinced that such a bridge exists you can also bring tools in the return/volatility space back into the efficiency/robustness space by applying the appropriate inverse transformations. Maybe the conclusions are common sense, but I'd still read a blog framing that process by way of analogy.