@article{PNA_2008_2008_1_a0,
     author = {Radford, Luis},
     title = {Diagrammatic {Thinking:} {Notes} on {Peirce{\textquoteright}s} {Semiotics} and {Epistemology.}},
     journal = {PNA},
     pages = {1-18},
     year = {2008},
     volume = {3},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PNA_2008_2008_1_a0/}
}