000 002770000a22001210004500
245 _aThe principles of scientific research
100 _aFreedman, Paul
260 _aLondon
_bMacdonald
_c1949
300 _a222 p.
080 _a5.001.5
_bF7
041 _aEN
942 _cBK
999 _c52996
_d52996