\[
\boxed{
{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right) +a \left( {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}p \left( x \right)  \right) {\frac {\rm d}{{\rm d}x}}y \left( x \right) + \left( a+bp \left( x \right) -4\,na \left( p \left( x \right)  \right) ^{2} \right) y \left( x \right) =0}
\]