Homotopy sequence of a topological groupoid with a basegroup and an   obstruction to presentability of proper regular Lie groupoids
  A topological groupoid G is K-pointed, if it is equipped with a homomorphism from a topological group K to G. We describe the homotopy groups of such K-pointed topological groupoids and relate these groups to the ordinary homotopy groups in terms of a long exact sequence. As an application, we give an obstruction to presentability of proper regular Lie groupoids. 
B. Jelenc, J. Mrcun
math.DG math.AT