1. Problems of reduction in experimental studies;Pyt'yev;Matem. Sb.,1983
2. Methods of reduction of measurements in Hilbert spaces;Pyt'yev;Matem. Sb.,1985
3. The pseudo-inverse operator. Properties and applications;Pyt'yev;Matem. Sb.,1982
4. Accuracy of metering converters;Azizov,1975