This must come from the name ***Weierstrass normal form*** given to the elliptic integrals
$$
\int\frac{ds}{\sqrt{4s^3-g_2s-g_3}},\quad
\int\frac{s\,ds}{\sqrt{4s^3-g_2s-g_3}},\quad
\int\frac{ds}{(s-\alpha)\sqrt{4s^3-g_2s-g_3}}
$$
in Weierstrass-Schwarz ([1885](//zbmath.org/?q=an:17.0419.01), p. 86), Burkhardt ([1899](//zbmath.org/?q=an:30.0396.01), p. 161), Fricke ([1913](//zbmath.org/?q=an:44.0521.09), [pp. 253, 294, 297](//archive.org/details/encyklomath202encyrich/page/n278)),...