00326nam a2200121 a 450000500170000002000150001708200140003210000210004624500680006725000120013526000350014730000220018220251203091540.0  a0415043182  a121,bpop  aPopper, Karl, R.  aConjectures and refutations: the growth of scientific knowledge  a5th ed.  aLoNew Delhion: Routledgec1989  axiv,432p.c22 cm.