//! [3]: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3351.pdf
//! [4]: http://en.wikipedia.org/wiki/Strict_weak_ordering
template <typename Ord>
//! [3]: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3351.pdf
//! [4]: http://en.wikipedia.org/wiki/Strict_weak_ordering
template <typename Ord>