“…The matrix ansatz of section VI (which gives the weights of the microscopic configurations in the steady state) has been generalized to describe the steady state of several other systems [12,62,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124], with of course modified algebraic rules for the matrices the vectors W | and |V .…”