  The correlation functions of the spin-1/2 XXZ spin chain in the ground state
are expressed in the form of the multiple integrals. For -1< Delta <1, they
were obtained by Jimbo and Miwa in 1996. Especially the next nearest-neighbour
correlation functions are given as certain three-dimensional integrals. We
shall show these integrals can be reduced to one-dimensional ones and thereby
evaluate the values of the next nearest-neighbor correlation functions. We have
also found that the remaining one-dimensinal integrals can be evaluated
analytically, when nu = arccos(Delta)/pi is a rational number.
