Porter, T. C., Schantz, F., Reichel, W. C., Richards, M., Grumbine, L. L., Kuhns, O. L., . . . Sachse, J. F. (1896). The Pennsylvania-German in the field of the natural sciences. Reading, PA: Society.

Porter, Thomas Conrad, F.J.F Schantz, William Cornelius Reichel, M.H Richards, Lee Light Grumbine, Oscar L. Kuhns, Paul De Schweinitz, and Julius Friedrich Sachse. The Pennsylvania-German in the Field of the Natural Sciences. Reading, PA: Society, 1896.

Porter, Thomas Conrad, et al. The Pennsylvania-German in the Field of the Natural Sciences. Reading, PA: Society, 1896.