Seeing Through Arithmetic 5Maurice L. Hartung, Henry Van Engen, Lois Knowles · First published 1963Open the Tome
Seeing through arithmeticHenry Van Engen, Lois Knowles, Maurice L. Hartung · First published 1961Open the Tome
The Learning of Mathematics Its Theory and PracticeHoward F. Fehr, Maurice L. Hartung, Henry Van Engen, Henry W. Syer · First published 1955Open the Tome
