A study of the bibliographies of a large number of articles in physics and electrical engineering indicates that definite patterns exist for the flow of technical information. Quantitative data are presented on the flow of information between countries, between cultural and functional groups, and between past and present. An analysis of the numerical data indicates that these flow patterns are deeply rooted in the dynamics and evolution of scientific thought and engineering development. The analysis also discloses that extreme asymmetry exists between journals in their capacity as carriers of scientific information.