This award supports collaboration between Dr. Shiferaw Berhanu of Temple University and Dr. Jorge G. Hounie of the Universidade Federal de Sao Carlos in Sao Carlos, Brazil to study a number of properties of solutions of systems of complex vector fields with smooth or real analytic coefficients. In cases to be considered, an integrability condition is always assumed to hold. These problems are motivated by classical results of holomorphic functions in one and several complex variables. Results from this research may have important applications to function theory in several variables and to the theory of linear partial differential equations.