Ablikim, M., Achasov, M.N., Ai, X.C., Yüncü, A., et.al., "Measurement of the e(+)e(-) -> eta J/psi Cross Section and Search for e(+)e(-) -> pi(0)J/psi at Center-of-Mass Energies Between 3.810 and 4.600 GeV", Physical Review D, 91, 11, 2015.