An investigation by T. Fujita and A. Arima ("Nucl. Phys. 1975") found the M-L rule to yield results closer to the measured values than did calculations based upon nuclear theory. The rule has been applied to isotopes of elements including mercury, iridium, gold, thallium, platinum, tungsten, osmium, and barium. T. Asaga, "et al." have proposed measuring the systematics of the nuclear properties of a series of europium isotopes to test the universality of the rule ("Z. Phys. 1997"). Researchers at Mainz, S. Trapp "et al." ("Hyperfine Interactions, 2000") have indicated that they plan to pursue experimental europium measurements. Author Clifford A. Pickover has granted permission to use information which is in his recent book, "Archimedes to Hawking: Laws of Science and the Great Minds Behind Them ", Oxford University Press, 2008,