2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/53807We discuss charged string solutions of the effective equations of D=4 heterotic string theory with non-constant dilaton and modulus fields. The effective action contains a generic moduli-dependent coupling function in the gauge field kinetic term and a non-perturbative scalar potential. This is a review of hep-th/9307123 by M. Cvetic and the author. To be published in the Proceedings of 27-th International Symposium on Theory of Elementary Particles, Wendisch - Rietz, September 1993.14 pages, harvmac, Imperial/TP/93-94/15High Energy Physics - Theorytext