Integral operators and complete families of solutions for(Delta _{p + 2}^2 uleft( {underset{ aise0.3emhbox{(smash{scriptscriptstyle hicksim})}}{x} } ight) + Aleft( {r^2 } ight)Delta _{p + 2} uleft( {underset{ aise0.3emhbox{(smash{scriptscriptstyle hicksim})}}{x} } ight) + B(r^2 )uleft( {underset{ aise0.3emhbox{(smash{scriptscriptstyle hicksim})}}{x} } ight) = 0)