@article{55353,
      author = {Nagel, Ernest,},
      url = {http://library.usi.edu/record/55353},
      title = {The structure of science; problems in the logic of  scientific explanation.},
      publisher = {Harcourt, Brace & World},
      recid = {55353},
      pages = {618 p.},
      address = {New York,},
      year = {1961},
}