Systematics of q anti-q states in the (n,M^2) and (J,M^2) planes
  In the mass region up to M < 2400 MeV we systematise mesons on the plots (n,M^2) and (J,M^2), thus setting their classification in terms of n^{2S+1}L_J q anti-q states. The trajectories on the (n,M^2)-plots are drawn for the following (IJ^{PC})-states: a_0(10^{++}), a_1(11^{++}), a_2(12^{++}), a_3(13^{++}), a_4(14^{++}), pi(10^{-+}), pi_2(12^{-+}), eta(00^{-+}), eta_2(02^{-+})$, rho(11^{--}), f_0(00^{++}), f_2(02^{++}). All trajectories are linear, with nearly the same slopes. At the (J,M^2)-plot we set out meson states for leading and daughter trajectories: for pi, rho, a_1, a_2 and P'. 
A.V. Anisovich, V.V. Anisovich, and A.V. Sarantsev