Open manifold with nonnegative Ricci curvature and collapsing volume
  In this paper, an n-dimensional complete open manifold with nonnegative Ricci curvature and collapsing volume has been investigated. If its radial sectional curvature bounded from below, it shows that such a manifold is of finite topological type under some restrictions shown below. 
Jing Mao
math.DG math.GT