Abelian Functions for Trigonal Curves of Genus Three
  We develop the theory of generalized Weierstrass sigma- and \wp-functions defined on a trigonal curve of genus three. In particular we give a list of the associated partial differential equations satisfied by the \wp-functions, a proof that the coefficients of the power series expansion of the sigma-function are polynomials of moduli parameters, and the derivation of two addition formulae. 
J. C. Eilbeck, V. Z. Enolski, S. Matsutani, Y. \^Onishi and E.   Previato