@techreport{SchmidtMaerz1995, author = {Frank Schmidt and Reinhard M{\"a}rz}, title = {On the Reference Wave Vector pf Paraxial Helmholtz Equations}, institution = {ZIB}, address = {Takustr. 7, 14195 Berlin}, number = {SC-94-38}, language = {eng}, year = {1995} }