1. Refrigeration methods and apparatus;Longsworth,1971
2. Total cryogen recondensation for mobile MRI;Murray,1986
3. Cryogenic cooling options for superconducting MRI magnets;Longsworth,1984
4. 4 K refrigerators with a new compact heat exchanger;Longsworth,1985
5. Detector for trace amounts of nitrogen in helium;Walker;Cryogenics,1986