MR0355229
Salzberg, P. M. and Seibert, P.
P. M. SALZBERG and P. SEIBERT
A Necessary and Sufficient Condition for the Existence of a Liapunov Function
Funkcialaj Ekvacioj. Serio Internacia
16
1973
97--101
http://fe.math.kobe-u.ac.jp/FE/Free/vol16/fe16-2-4.pdf
http://fe.math.kobe-u.ac.jp/FE/FE_pdf_with_bookmark/FE11-20-en_KML/fe16-097-101/fe16-097-101.pdf
http://www.ams.org/mathscinet-getitem?mr=MR0355229
fe16-097-101
1973
A Necessary and Sufficient Condition for the Existence of a Liapunov Function
Salzberg, P. M. and Seibert, P.
Salzberg, P. M. and Seibert, P.
1
Bhatia, N. P.; Szegö, G. P.
Stability Theory of Dynamical Systems
Springer, New York-Heidelberg-Berlin
1970
MR0289890
2
Seibert, P.
A unified theory of Liapunov stability
Funkcial. Ekvac.
15
1972
139-147
MR0333376
0333376