@article{1206139400,
author = {Ohtsuka, Makoto},
title = {Extremal length of level surfaces and orthogonal trajectories},
journal = {J. Sci. Hiroshima Univ. Ser. A-I Math.},
volume = {28},
number = {2},
year = {1964},
pages = { 259-270},
language = {en},
url = {http://dml.mathdoc.fr/item/1206139400}
}
Ohtsuka, Makoto. Extremal length of level surfaces and orthogonal trajectories. J. Sci. Hiroshima Univ. Ser. A-I Math., Tome 28 (1964) no. 2, pp. 259-270. http://gdmltest.u-ga.fr/item/1206139400/