@article{10_4064_aa_52_2_103_117,
     author = {Kenneth Hardy and Kenneth Williams},
     title = {The class number of pairs of positive-definite binary quadratic forms},
     journal = {Acta Arithmetica},
     pages = {103--117},
     publisher = {mathdoc},
     volume = {52},
     number = {2},
     year = {1989},
     doi = {10.4064/aa-52-2-103-117},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/aa-52-2-103-117/}
}