Lawson, J. L., & Uhlenbeck, G. E. (1950). Threshold signals. McGraw-Hill.

Lawson, James L., and G. E. Uhlenbeck. Threshold Signals. N.Y.: McGraw-Hill, 1950.

Lawson, James L., and G. E. Uhlenbeck. Threshold Signals. McGraw-Hill, 1950.