An Inverse Function of an Abelian Integral. Abelian functions have two variables and four periods. They are a generalization of Elliptic Functions, and are also called Hyperelliptic Functions.
See also Abelian Integral, Elliptic Function
References
Abelian Functions
Baker, H. F. Abelian Functions: Abel's Theorem and the Allied Theory, Including the Theory of the Theta Functions.
New York: Cambridge University Press, 1995.
Baker, H. F. An Introduction to the Theory of Multiply Periodic Functions. London: Cambridge University Press, 1907.