@article{Levkova:2009wK, author = "Levkova, Ludmila", title = "{Contributions of the disconnected diagrams in the hyperfine splitting in charmonium in the quenched case }", doi = "10.22323/1.066.0133", journal = "PoS", year = 2009, volume = "LATTICE 2008", pages = "133" }