On the strong uniqueness of a solution to singular stochastic   differential equations
  We prove the existence and uniqueness of a strong solution for an SDE on a semi-axis with singularities at the point 0. The result obtained yields, for example, the strong uniqueness of non-negative solutions to SDEs governing Bessel processes. 
Olga V. Aryasova, Andrey Yu. Pilipenko
math.PR