Bounded p-valent Robertson functions defined by using a differential operator

Let FM(λ,α,p,q)(M>12,|λ|<π/2,0≤αq) denote the class of functions f(z)=zp+∑k=p+1∞akzk analytic in U={z:|z|<1} which satisfy for fixed M, z=reiθ∈U andeiλzf(1+q)(z)f(q)(z)−αcosλ−i(p−q)sinλ(p−q−α)cosλ−M12,|λ|<π/2,0≤αq) denote the class of bounded p-valent λ-Robertson functions of order α,0≤α