A Note on Spectral Analysis in Automorphic Representation Theory for   ${\rm GL}_2$: II
  We generalize Zagiers work on regularized integral to the singular case in the adelic setting. We develop necessary tools of treating various singular cases of regularized triple product formulas, which appear naturally in the work of Michel and Venkatsh on the subconvexity problem for $GL_2$. 
Han Wu
math.NT