Integral Signs

In calculus, we meet this fellow:

∫

And in multivariable calculus, we meet these folks:

∬ ∭

If we go on to complex analysis, we meet this guy:

∮

But what's a legitimate usage of these guys?  

∯ ∰

Are they deprecated symbols which are avoided in favor of the above, with slightly different notation?  Are they only used in complex analysis?

>>7
But at least you now understand the use of closed integrals, right?