Hoffmann, W. & Wakatsuki, S. (2018). On the Geometric Side of the Arthur Trace Formula for the Symplectic Group of Rank 2. MEMOIRS OF THE AMERICAN MATHEMATICAL SOCIETY, 255(1224), 1-+. Amer Mathematical Soc.
Hoffmann, W. (2008). Geometric estimates for the trace formula. ANNALS OF GLOBAL ANALYSIS AND GEOMETRY, 34(3), 233-261. SPRINGER. doi:10.1007/s10455-008-9105-0.
