Fat Hoffman graphs with smallest eigenvalue greater than -3
  In this paper, we give a combinatorial characterization of the special graphs of fat Hoffman graphs containing $\mathfrak{K}_{1,2}$ with smallest eigenvalue greater than -3, where $\mathfrak{K}_{1,2}$ is the Hoffman graph having one slim vertex and two fat vertices. 
Akihiro Munemasa, Yoshio Sano, and Tetsuji Taniguchi
math.CO cs.DM