Kwakkelstein, M. W. (1994). Leonardo da Vinci as a physiognomist: Theory and drawing practice / by Michael W. Kwakkelstein. Primavera Pers.
Lua i Stíl Chicago (17ú heag.)Kwakkelstein, Michael W. Leonardo Da Vinci as a Physiognomist: Theory and Drawing Practice / by Michael W. Kwakkelstein. Leiden: Primavera Pers, 1994.
Lua MLA (8ú heag.)Kwakkelstein, Michael W. Leonardo Da Vinci as a Physiognomist: Theory and Drawing Practice / by Michael W. Kwakkelstein. Primavera Pers, 1994.
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