Stability notions for systems of ordinary and functional differential
equations were investigated by many authors. Our purpose in this paper
is to study sufficient conditions of different types of stability, an
d improvements of some results of Athanassov, Yone-yama, and Li-Fu. Fu
rthermore, we show that the condition V'(t, 0) less than or equal to 0
is not sometimes a necessary condition for stability results. (C) 199
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