An integral criterion for the
(
m
,
n
−
m
)
(m,n - m)
-disfocality
(
1
⩽
m
⩽
n
−
1
)
(1 \leqslant m \leqslant n - 1)
on
[
a
,
b
]
[a,b]
of a linear nth order differential equation is given. The criterion is analogous to that of Lyapunov (1947) and Nehari (1962).