@article{10_4171_dm_446,
     author = {Manabu Murata},
     title = {On quadratic {Diophantine} equations in four variables and orders associated with lattices},
     journal = {Documenta mathematica},
     pages = {247--284},
     year = {2014},
     volume = {19},
     doi = {10.4171/dm/446},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/dm/446/}
}