Report by General Electric into a 1978-1985 program to develop a more fuel efficient turbofan engine.
Source:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900019242_1990019242.pdf
Source:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19900019242_1990019242.pdf