\[
\boxed{
{\frac {{\rm d}^{3}}{{\rm d}{x}^{3}}}y \left( x \right) -3\, \left( 2\,{\it WeierstrassP} \left( x,{\it g2},{\it g3} \right) +a \right) {\frac {\rm d}{{\rm d}x}}y \left( x \right) +by \left( x \right) =0}
\]