Prince E
Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
Acta Crystallogr D Biol Crystallogr. 1993 Jan 1;49(Pt 1):61-5. doi: 10.1107/S0907444992009740.
Methods for constructing everywhere-positive electron-density maps with Fourier amplitudes matching those for arbitrarily large sets of observed data, utilizing dual-function methods for maximization of entropy, are described. Possible strategies for utilizing these maps for the determination and extension of phases in macromolecular structure determination are suggested, and problems are discussed.