1. RD 34.17.302-97 (OP 501 TsD-97): Steam and Water Boilers. Steam and Hot Water Pipelines. Vessels. Welded Joints, Quality Control. Ultrasonic Control. Basic Regulations, Moscow: NPP Norma, 1997.
2. Ushakov, V.M., The Use of Angle Piezoelectric Transducers for Flaw Detection in Austenitic Welded Joints, V Mire Nerazrush. Kontrolya, 2003, no. 1 (19), pp. 19–21.