Geodesic
Radial projection and the Poincaré metric
Zapiski Nauchnykh Seminarov POMI, Analytical theory of numbers and theory of functions. Part 14, Tome 237 (1997), pp. 148-160 
A. Yu. Solynin. Radial projection and the Poincaré metric. Zapiski Nauchnykh Seminarov POMI, Analytical theory of numbers and theory of functions. Part 14, Tome 237 (1997), pp. 148-160. http://geodesic.mathdoc.fr/item/ZNSL_1997_237_a11/
@article{ZNSL_1997_237_a11,
     author = {A. Yu. Solynin},
     title = {Radial projection and the {Poincar\'e} metric},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {148--160},
     year = {1997},
     volume = {237},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1997_237_a11/}
}
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Voir la notice du chapitre de livre provenant de la source Math-Net.Ru

Some estimates for the Poincaré metric of a planar domain are obtained in terms of the radial projection of the complement of the domain onto the unit circle. These estimates allow us, in particular, to strengthen the well-known Lavrent'ev theorem on the product of conformal radii of nonoverlapping domains. The proofs use the polarization transformation.