In Germany, I know about one guy working on fuzzy logic in systems theory (Thomas Kron:: http://www.soziologie.rwth-aachen.de/ca/dv/tca/?lang=de). Maybe you can find something there...
for some work on fuzzy sets in the measurement of mutidimensional poverty, see ao the work of Alessio Fusco (CEPS/INSTEAD, Luxembourg), who wrote his phd on this.
Fiss, P. C. (2007). A set-theoretic approach to organizational configurations. Academy of management review, 32(4), 1180-1198.
An example:
Fiss, P. C. (2011). Building better causal theories: A fuzzy set approach to typologies in organization research. Academy of Management Journal, 54(2), 393-420.