[271] Bounded orthogonal systems and the Λ($p$)-set problem

[272] On a class of diophantine equations of the second degree in imaginary quadratic fields

[273] On some classes of homogeneous ternary cubic diophantine equations

[274] Jordan decomposition for a class of singular differential operators

[275] Desingularization of non-dicritical holomorphic foliations and existence of separatrices