Acta Applicandae Mathematicae
We use the theory of reduction of exterior differential systems with symmetry to study the problem of using a symmetry group of a differential equation to find noninvariant solutions.
Anderson, I. M., & Fels, M. E. (2005). Exterior Differential Systems with Symmetry. Acta Applicandae Mathematicae, 87, 3-31. doi:10.1007/s10440-005-1136-y
Published by Springer in Acta Applicandae Mathematicae. Author Preprint available for download through link above.