1. DIML International Recommendation No. 30 (1987): End Standards of Length (Gauge Blocks); In, Chapt III, Verification Methods for Reference End Gauges.
2. VDI/VDE 2617 (1986). Genauigkeit von Koordinatenmessgeräten, Verein Deutscher Ingenieure, Dusseldorf, GFR.
3. BS6808: (Parts 1-3): 1987. Coordinate Measuring Machines. British Standards Institution.
4. JIS B7440: Test Code for Accuracy of Coordinate Measuring Machines. Japan Industry Standard.
5. Schüssler, H.-H. (1982). A biaxial laser interferometer for absolute calibration of bidirectional step gauges and gauge blocks - Paper P. 17.2 IMEKO May '82, Berlin.