Liouville J. [1862] Sur la forme $x^2+2y^2+2z^2+4t^2$, $x^2+8(y^2+z^2+t^2)$, $x^2+4y^2+4z^2+8t^2$, $x^2+8y^2+8z^2+16t^2$, $x^2+2y^2+4z^2+4t^2$, $x^2+2y^2+8z^2+8t^2$, $x^2+8y^2+16z^2+16t^2$, $x^2+4y^2+4z^2+16t^2$, $x^2+2y^2+2z^2+4t^2$, $x^2+y^2+4z^2+8t^2$, $x^2+4y^2+16z^2+16t^2$, $x^2+y^2+8z^2+8t^2$, $x^2+4y^2+8z^2+8t^2$, $x^2+y^2+16z^2+16t^2$, $x^2+4y^2+8z^2+16t^2$, $x^2+2y^2+16z^2+16t^2$, $x^2+2y^2+2z^2+8t^2$, $x^2+2y^2+4z^2+16t^2$, $x^2+2y^2+8z^2+16t^2$, $x^2+y^2+2z^2+8t^2$, $x^2+y^2+4z^2+16t^2$, $x^2+2y^2+2z^2+16t^2$, $x^2+y^2+z^2+16t^2$. J.M. 7, 1-16, 62-76, 99-120, 143-168.
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Liouville J. [1863] Sur la forme $x^2+y^2+z^2+3t^2$, $x^2+y^2+2z^2+2zt+2t^2$, $x^2+y^2+z^2+zt+t^2$, $x^2+y^2+2z^2+6t^2$, $x^2+2y^2+2z^2+3t^2$, $x^2+xy+y^2+z^2+zt+t^2$, $x^2+y^2+z^2+12t^2$, $x^2+2y^2+2z^2+12t^2$, $x^2+y^2+4z^2+12t^2$, $x^2+4y^2+4z^2+12t^2$, $3x^2+4y^2+4z^2+12t^2$, $x^2+y^2+3z^2+4t^2$, $x^2+3y^2+4z^2+4t^2$, $2x^2+2y^2+3z^2+4t^2$, $x^2+y^2+z^2+3t^2$, $x^2+4y^2+12z^2+16t^2$, $x^2+3y^2+6z^2+6t^2$, $2x^2+3y^2+3z^2+6t^2$, $x^2+3(y^2+z^2+t^2)$. J.M. 8, 105-133, 141-144, 161-224.
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Liouville J. [1863] Sur la forme $2x^2+2xy+2y^2+3(z^2+t^2)$, $x^2+xy+y^2+3(z^2+t^2)$, $3x^2+3y^2+3z^2+4t^2$, $3x^2+3y^2+4z^2+12t^2$, $3x^2+4y^2+12z^2+12t^2$, $x^2+3y^2+3z^2+12t^2$, $x^2+3y^2+12z^2+12t^2$, $x^2+12y^2+12z^2+12t^2$, $3x^2+4y^2+12z^2+48t^2$, $x^2+y^2+3(z^2+t^2)$, $x^2+xy+y^2+2z^2+2zt+2t^2$. J.M. 8, 225-256, 296, 308-310.
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