Giovanni Amelino-Camelia, "Doubly-Special Relativity: First Results and Key Open Problems." Int. J. Mod. Phys. D11 (2002) 1643. Online copy at http://arxiv.org/abs/gr-qc/0210063
... with no husband present, and 37.4% are non-families. 31.6% of all households are made up of individuals and 12.1% have someone living alone who is 65 years of ag ...