GAZI UNIVERSITY JOURNAL OF SCIENCE, vol.28, no.2, pp.265-267, 2015 (ESCI)
We transfer the recent obtained result of univariate Lyapunov-type inequality for third order differential equations to the multivariate setting of a shell via the polar method. Our result is better than the result of Anastassiou [Appl. Math. Letters, 24 (2011), 2167-2171] for third order partial differential equations.