Gw mau tau Penerbitan dari Val Logsdon Fitch. Jelasin dalam bahasa melayu

Fitch, V. "Some Notes on Wideband Feedback Amplifiers", Los Alamos National Laboratory, United States Department of Energy (through predecessor agency the Atomic Energy Commission), (March 16, 1949).

Fitch, V. "A High Resolution Scale-of-four", Columbia University, United States Department of Energy (through predecessor agency the Atomic Energy Commission), (August 25, 1949).