Mechanics of Apparent Horizon in Two Dimensional Dilaton Gravity
  In this article, we give a definition of apparent horizon in a two dimensional general dilaton gravity theory. With this definition, we construct the mechanics of the apparent horizon by introducing a quasi-local energy of the theory. Our discussion generalizes the apparent horizons mechanics in general spherically symmetric spactimes in four or higher dimensions to the two dimensional dilaton gravity case. 
Rong-Gen Cai and Li-Ming Cao
gr-qc