@article{80068,
      author = {Wolf, A.},
      url = {http://library.usi.edu/record/80068},
      title = {Textbook of logic,},
      publisher = {G. Allen & Unwin, ltd.},
      recid = {80068},
      pages = {455 p.},
      address = {London,},
      year = {1951},
}