1. Test results of liquid level point sensor operation in liquid hydrogen;Burgeson;NBS Report No. 9231,1966
2. Selecting liquid level transducers for cryogenic service;Burgeson;NBS Report No. 8784,1965
3. The performance of point level sensors in liquid hydrogen;Burgeson,1964
4. Discrete liquid/vapor detectors for use in liquid helium;DiPirro,1990