1. A. M. Lyapunov, The General Problem of the Stability of Motion (Mathematical Society of Kharkov, Kharkov, 1892) [Int. J. Control 55 (3), 531–773 (1992)].
2. E. A. Barbashin and N. N. Krasovskii, “On the stability of motion in the large,” Dokl. Akad. Nauk SSSR 86, 453–456 (1952).
3. N. N. Krasovskii, Certain Problems in the Theory of Stability of Motion (Fizmatlit, Moscow, 1959) [in Russian].
4. J. P. La Salle, “Some extentions of Liapunov‘s second method,” IRE Trans. CT-7, 520–527 (1960).
5. V. M. Matrosov, “On the stability of motion,” Prikl. Mat. Mekh. 26 (5), 885–895 (1962) [J. Appl. Math. Mech. 26 (5), 1337–1353 (1962)].