[boost] Is there a one-to-one map class in boost?

Hello, Now I'm finding a one-to-one map class, say map1, that support the following syntax: map1 m; m.insert(std::make_pair(k1, v1)); ... key k; value v; v = m[k]; k = m[v]; I know a pair of std::map could provide such functionality. But I think a single obj, if that class exists, would be more elegant. Is there such a class in boost? Thanks Max