Athreya, SMartin, BarlowRich, BassPerkins, Edwin A2012-02-052012-02-052002Probability theory and related fields,V123,p484-520http://hdl.handle.net/10263/3164enStochastic differential equationsMartingale problemElliptic operatorsDegenerate operatorsDiffusionsBessel processesDegenerate stochastic differential equations and super markov chainsArticle