Bullentin of research laboratory of precision machinery and electronics.. v. 41 / Bullentin of research laboratory of precision machinery and electronics.. v. 42 / Bullentin of research laboratory of precision machinery and electronics.. v. 43 / Bulletin of Research Laboratory of Precision Machinery and Electronics.. no. 44. Bulletin of Research Laboratory of Precision Machinery and Electronics.. no. 45. Bulletin of Research Laboratory of Precision Machinery and Electronics.. no. 46. Bulletin of Research Laboratory of Precision Machinery and Electronics.. no. 47 Bulletin of Research Laboratory of Precision Machinery and Electronics.. no. 49 Bulletin of Research Laboratory of Precision Machinery and Electronics.. no. 50