TITLE: Uses for esoteric integral symbols
QUESTION [16 upvotes]: A while ago, I was searching for a TeX package which would provide a double integral symbol with a circle which I could use to typeset some lecture notes on surface integrals.  I happened upon the esint package, which includes several integral symbols I had never seen before.  In particular, integral symbols with a square (\sqint and \sqiint), a sloped dash (\fint) and the very curious \landupint and \landdownint.  Is anyone familiar with any uses for these symbols?

Added (TB) Here's an image of the integral signs in question:

REPLY [5 votes]: The circles with arrows are useful for contour-integrals in complex analysis.
The \landupint and \landdonwint are probably used to expres contourintegrals that go around a singularity by integrating around the boundary of half of a circle ($\partial B(x,\epsilon)$) and letting $\epsilon\to 0$. I've never seen that symbol being used in practice, but it's what the picture suggests.