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N.K.Ribarska, On the property “countable cover by sets of small local diameter”, Studia Mathematica 140, 2 (2000), 99-116.
N.K.Ribarska, Ts.Y.Tsachev, M.I.Krastanov, A note on “On a critical point theory for multivalued functionals and applications to partial differential inclusions”, Nonlinear Analysis 43 (2001), 153-158.
N.K.Ribarska, V.D.Babev, A stability property for locally uniformly rotund renorming, to appear in Mathematika.
Degiovanni M, Lucchetti R, Ribarska N., Critical point theory for vector valued functions, JOURNAL OF CONVEX ANALYSIS 9 (2): 415-428 2002