[1] W. Bonnice, R. Silverman: 
The Hahn-Banach extension and the least upper bound properties are equivalent. Proc. Amer. Math. Soc. 18 (1967), 843 - 850. 
MR 0215050 | 
Zbl 0165.46802 
[2] J. M. Borwein: 
Continuity and differentiability properties of convex operators. Proc. London Math. Soc. 44 (1982), 3, 420-444. 
MR 0656244 | 
Zbl 0487.46026 
[3] J. M. Borwein: 
On the Hahn-Banach extension property. Proc. Amer. Math. Soc. 86 (1982), 1,42-46. 
MR 0663863 | 
Zbl 0499.46002 
[4] K.-H. Elster, J. Thierfelder: 
A general concept on cone approximations in nondifferentiable optimization. In: Nondifferentiable Optimization: Motivations and Applications (V. F. Demjanov; D. Pallaschke, eds.).(Lecture Notes in Economics and Mathematical Systems vol. 255.) Springer-Verlag, Berlin-Heidelberg-New York-Tokyo 1985, pp. 170-189. 
MR 0822014 
[5] R. B. Holmes: 
Geometric Functional Analysis and its Applications. Springer-Verlag, Berlin-Heidelberg-New York 1975. 
MR 0410335 | 
Zbl 0336.46001 
[7] G. Jameson: 
Ordered Linear Spaces. (Lecture Notes in Mathematics, vol. 141.) Springer- Verlag, Berlin -Heidelberg-New York 1970. 
MR 0438077 | 
Zbl 0196.13401 
[8] G. Köthe: 
Topologische Lineare Raume I. Springer-Verlag, Berlin-Heidelberg-New York 1966. 
MR 0194863 
[9] R.   Nehse: 
The   Hahn-Banach   property  and  equivalent  conditions. Comment.   Math. Univ. Carolinae 19 (1978), 1, 165-177. 
MR 0492379 | 
Zbl 0373.46011 
[10] R. Nehse: 
Separation of two sets in product spaces. Math. Nachrichten 97 (1980), 179-187. 
MR 0600832 
[12] A. L. Peressini: 
Ordered Topological Vector Spaces. Harper and Row, New York-Evanston-London 1967. 
MR 0227731 | 
Zbl 0169.14801 
[13] J. Thierfelder: 
Nonvertical affine manifolds and separation theorems in product spaces (to appear).  
MR 1121215 
[14] T. O. To: 
The equivalence of the least upper bound property and the Hahn-Banach property in ordered linear spaces. Proc. Amer. Math. Soc. 30 (1971), 287-295. 
MR 0417746 
[15] M. Valadier: 
Sous-differentiabilité des fonctions convexes a valeurs dans un espace vectoriel ordoné. Math. Scand. 30 (1972), 65-74. 
MR 0346525 
[16] J. Zowe: 
Subdifferential of convex functions with values in ordered vector spaces. Math. Scand. 34(1974), 69-83. 
MR 0380400