Wu and Whttney 
By substituting (9) in (26), we readily obtain 
a(é) P(e) - b(&)Hy [T]+ H, [br] - , [c()H,[r]] = 
- -H, [al] - p(é) 
Upon using the Poincaré-Bertrand formula (with appropriate assump- 
tions) for the last term on the left side of the above equation, there 
results 
where 
il 
gi) = ae me 
This is a Fredholm integral equation of the second kind, with a regul- 
ar symmetric kernel, for which a well-developed theory is available. 
(ii) Singular integral equation method 
When the coefficients a,b,c, satisfy the following relation- 
ship 
a( &)otine(te) o>it) Dian bl &)S bo Sane bo = const , (29) 
the system of equations (26) and (9) can be reduced in succession 
to a single integral equation, each time for a single variable, and 
these equations are of the Carleman type, which can be solved by 
known methods (see Muskhelishvili 1953), yielding the final solution 
in a closed form. 
In the first step we multiply (9) by bo, and subtracting it 
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