TITLE: closed geodesics are dense in both hyperbolic surface and unit tangent bundle of hyperbolic surface
QUESTION [5 upvotes]: Could you please recommend me some references for proofs of this fact: "closed geodesics are dense in both hyperbolic surface and unit tangent bundle of hyperbolic surface". Thanks in advance!

REPLY [7 votes]: See the paper MR1763264 by Marcos Salvai. Here is a link to the paper.