compare boost::geometry::model::box

is it already implemented functions in boost to compare squares of boost::geometry::model::box? I need to find among the vector of boost::geometry::model::box one with the smallest square. From https://www.boost.org/doc/libs/1_65_1/libs/geometry/doc/html/geometry/reference/models/model_box.html it seems they don't have overloaded compression operators, so I need to manually calculate the squares and then compare them, or there is something already for that in boost? And in general is there some general documentation in boost?