I'm looking for a symbol that merges
\oint together (a dedicated package, if it could exist, would provide something like
The purpose of
\oint is to show that the integration path is closed (it is often used in the definition of the circulation), but the adding one (or two) more integral it is emphasized that the integral is calculated over a surface (
\oiint) or over a volume (
Do these symbols exist in the world of LaTeX?