@article{GDZPPN002061899,
title = {Extremal Length, Extremal Regions and Quadratic Differentials.},
journal = {Commentarii mathematici Helvetici},
volume = {50},
year = {1975},
pages = {455-476},
zbl = {0322.30012},
url = {http://dml.mathdoc.fr/item/GDZPPN002061899}
}
Rodin, B.; Minda, C.D. Extremal Length, Extremal Regions and Quadratic Differentials.. Commentarii mathematici Helvetici, Tome 50 (1975) pp. 455-476. http://gdmltest.u-ga.fr/item/GDZPPN002061899/