Rational integrals of geodesic flows

Polynomial (in momenta) integrals of geodesic flows, also known as Killing tensors of the metric, play an important role in finite-dimensional integrable systems. Recently, rational integrals came in focus of investigations. (These are natural, especially for algebraic Hamiltonian actions.) I will discuss the problem of their computations and count, relation to relative Killing tensors and show some examples.