Liouvillian first integrals for quadratic systems with an integrable saddle

Agraïments: The second author was supported by Portuguese National Funds through FCT - Fundacâo para a Ciência e a Tecnologia within the project PTDC/MAT/117106/2010 and by CAMGSD.We provide explicit expressions for the Liouvillian first integrals of the quadratic polynomial differential systems having an integrable saddle