La soledad del hombre. - Schachtel, Ernst G.; Fromm, Erich; Van den Haag, Ernest; Wright Mills, C.; Merton, Robert K.; Mumford, Lewis; Eaton, Joseph W.; Simmel, Georg; Titmuss, Richard M.; Marx, Karl; Weiss, Frederick A.; Anders, Gunther; et al. (Monte Avila, 1972)