Literary Encyclopedia
http://www.litencyc.com/php/stopics.php?rec=true&UID=1355
A further explanation of the term leitmotif.
Nobel Prizewinners
http://nobelprize.org/literature/laureates/1929/
Includes the text of Mann's Nobel acceptance speech.
Literature, Arts, and Medicine Database
http://mchip00.nyu.edu/lit-med/lit-med-db/webdocs/webauthors/mann142-au-.html
A medical perspective on Mann's work.
