@article{GDZPPN00242696X,
title = {Barta's Inequalities and the First Eigenvalue of a Cap Domain of a 2-Sphere.},
journal = {Mathematische Zeitschrift},
volume = {180},
year = {1982},
pages = {313-318},
zbl = {0498.53034},
url = {http://dml.mathdoc.fr/item/GDZPPN00242696X}
}
Sato, Sadao. Barta's Inequalities and the First Eigenvalue of a Cap Domain of a 2-Sphere.. Mathematische Zeitschrift, Tome 180 (1982) pp. 313-318. http://gdmltest.u-ga.fr/item/GDZPPN00242696X/