On the Gerchberg - Papoulis algorithm

In this paper, iterative procedures for band-limited signal extrapolation are considered. Specifically, we will show that the well-known Gerchberg-Papoulis algorithm [1], [2]:
g_{n} = \sin c_{\Omega} \ast (g + (I - T)g_{n-1})
, can be considered a special case of an iterative procedure given by Landweber in 1951 131.