@article{articled874ee1d,
title   = {Do the QCD sum rules support four-quark states?},
author = {Matheus, Ricardo D'Elia and Navarra, Fernando Silveira and Nielsen, Marina and Silva, R Rodrigues da},
year = {2007},
doi = {10.1103/physrevd.76.056005},
journal   = {Physical Review D}
}