Iv. Gaishun et Lb. Knyazhishche, STABILITY THEOREMS FOR DELAY EQUATIONS BY NONMONOTONOUS LIAPUNOV FUNCTIONALS, Doklady Akademii nauk BSSR, 38(3), 1994, pp. 5-8
New stability conditions for delay equations are presented in terms of
Liapunov functional V(t, x(t)). The change of a sign of the V(t, x(t)
) and V(t, x(t)) is possible.