The number of catenoids connecting two coaxial circles in   Lorentz-Minkowski space
  In 3-dimensional Lorentz-Minkowski space we determine the number of catenoids connecting two coaxial circles in parallel planes. This study is separated according to the types of circles and the causal character (spacelike and timelike) of the catenoid. 
Shintaro Akamine and Rafael L\'opez
math.DG