Noetherian symmetries of noncentral forces with drag term
  We consider the Noetherian symmetries of second-order ODEs subjected to forces with nonzero curl. Both position and velocity dependent forces are considered. In the former case the first integrals are shown to follow from the symmetries of the celebrated Emden-Fowler equation. 
A. Ghose-Choudhury, Partha Guha, Andronikos Paliathanasis and P.G.L.   Leach
math-ph math.CA math.MP physics.class-ph