Boundary harnack principle for denjoy domains

In this paper we are condidering positive, symmetric, harmonic functions in a Denjoy domain with uniformly perfect boundary that vanish continuously on the boundary of that domain. Given two such functions ν, υ we are proving that the ratio (ν/υ) can be extended to the boundary, and the extension is Holder continuous with exponent depending on the uniformly perfectness cnstants of the bundary.