A Rigorous Treatment of Division by Zero: By considering a new notion of division, one can allow division by zero, but the algebraic rules have to be modified.
The Digit Zero: Some information about the number zero and links to other pages.
Zero: A history of Zero that describes the introduction of zero and the main persons that brought advantages to it.
Zero in Four Dimensions: A paper discussing the historical, psychological, cultural, and logical perspectives of the number zero.