1. A Primer of Nonlinear Analysis;Ambrosetti,1993
2. Higher-order extremum conditions and tangent vectors at an abnormal point;Arutyunov;Dokl. Akad. Nauk,2001
3. Optimality Conditions: Abnormal and Degenerate Problems;Arutyunov,2000
4. Second-order conditions in extremal problems. The abnormal points;Arutyunov;Trans. Amer. Math. Soc.,1998
5. The implicit function theorem and abnormal points;Arutyunov;Dokl. Mat.,1999