Curl-Constrained Gradient Estimation for Image Recovery from Highly Incomplete Spectral Data Chiara Ravazzi, Giulio Coluccia, Enrico Magli (2017) Curl-Constrained Gradient Estimation for Image Recovery from Highly Incomplete Spectral Data, In: IEEE TRANSACTIONS ON IMAGE PROCESSING, pp. 2656-2668, ISSN: 1057-7149