@article{EUG_1990__25_a3,
     author = {Anthony W. Hager and  James  J. Madden},
     title = {Algebraic {Classes} of {Abelian} {Torsion-Free} and {Lattice-Ordered} {Groups}},
     journal = {E\ensuremath{\upsilon}\ensuremath{\kappa}\ensuremath{\lambda}\ensuremath{\varepsilon}\ensuremath{\acute\iota}\ensuremath{\delta}\ensuremath{\eta}\ensuremath{\varsigma} \ensuremath{\Gamma}
},
     pages = {53-63},
     publisher = {mathdoc},
     volume = {25},
     year = {1990},
     language = {gr},
     url = {http://geodesic.mathdoc.fr/item/EUG_1990__25_a3/}
}