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Improved lower bounds for the atomic charge density at the nucleus.
F.J. Gálvez, I. Porras, J.C. Angulo and J.S. Dehesa.
Journal of Physics B 21 (1988) L271-L274.
Atomic-charge convexity and the electron density at the nucleus.
J.C. Angulo, J.S. Dehesa and F.J. Gálvez.
Physical Review A 42 (1990) 641-644; erratum 43 (1991) 4069-4070.
New bounds for the atomic charge and momentum densities at the origin.
J.C. Angulo, J.S. Dehesa and F.J. Gálvez.
Zeitschrift für Physik D 18 (1991) 127-130.