(RT @contractio) [Luhmann][sociology]誰か…(ry / Parsons, Luhmann and the Theorem of Double Contingency http://htn.to/qNz5y3
(RT @contractio) [Luhmann][sociology]誰か…(ry / Parsons, Luhmann and the Theorem of Double Contingency http://htn.to/qNz5y3
