I Parameter Integration of Bubble Integral

Elmo
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Cant figure out how this PV bubble integral has been solved.
Referring to this link : https://qcdloop.fnal.gov/bubg.pdf
Using Mathematica Integrate command to solve it does not give the result stated here but I am unclear as to how they got to the result in the 4th line.
It is clear that the integrand (1st line) can diverge for certain values of the Feynman parameter λ and this is presumably why they find the roots of the expression in the denominator. I just dont know what they did to solve this loop integral and express the result in terms of the roots.
 
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Maybe they used some deformation of a complex contour for the ##\lambda## integral integrating somehow around the branch cut of the ln?
 
Just factor the quadratic argument of the logarithm as ##(\lambda-\lambda_1)(\lambda - \lambda_2)##, expand the logarithm into ##\log(\lambda - \lambda_1)+\log(\lambda - \lambda_2)## (modulo constant prefactors) and integrate by parts.
 
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