where 
= 1 for a call and = 1 for a put, , , , , ,

where 
w = The European option value S = The spot price of the underlying asset X = Strike price H = Barrier = Volatility of underlying asset b = Cost of carry r = Risk free rate t1 = End of monitoring period T2 = Expiry date M = The Cumulative bivariate normal density function N = The Cumulative normal density function 
See Also 
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