@article{10_4064_aa136_2_4,
     author = {Ay\c{s}e Alaca},
     title = {Representations by quaternary quadratic forms
 whose coefficients are 1, 3 and 9},
     journal = {Acta Arithmetica},
     pages = {151--166},
     publisher = {mathdoc},
     volume = {136},
     number = {2},
     year = {2009},
     doi = {10.4064/aa136-2-4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/aa136-2-4/}
}