1. A.D. Alexandroff, Almost everyuhene existence of the second dlfferential of a convex function and some properties of convex surfaces connected with it, Ucenye Zapiski Leningr. Gos. Univ. Ser. Mat. 37 n° 6, (1939) 3–35 (in Russian)
2. A.D. Alexandroff, On surfaces represented as the. difference of convex functions, Izv. Akad. Nauk Kaz. SSR 60, Ser. Mat. Mekh. 3, (1949) 3–20 (in Russian).
3. A.D. Alexandroff, Surfaces reprented by the diffexences of convex functions, Dokl. Akad. Nauk SSSR 72, (1959) 613–616 (in Russian).
4. G. Arsove, Functions representable. as the difference of subharmonic func-tions, Transactions Amer. Math. Soc. 75, (1953) 327–365.
5. J.-P. Aubin, Lipschitz behavior of solutions to convex minimization problems, Math. of Operations Research 9, n° 1 (1984) 87–111.