@article{1365172,
      note = {"September 1993, Volume 105, Number 503 (fourth of 6  numbers)."},
      author = {Makkai, Mihály,},
      url = {http://library.usi.edu/record/1365172},
      title = {Duality and definability in first order logic /},
      recid = {1365172},
      pages = {1 online resource (122 pages).},
}