**Issue Date** | Title | Author(s) | Publisher |

**1991 ** | Инвариантные подпространства в пространствах граничных значений аналитических функций в областях со спрямляемой границей | *Тумаркин, Г. Ц.* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | Concerning trivial maximal Abelian subalgebras of B(X) | *Zelazko, W.* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | On the classifications of unitary lowest weight representations of conformal current algebras | *Todorov, I. T.* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | Exponential approximation in the norms and semi-norms | *Pych-Taberska, Paulina; Taberski, Roman* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | The indecomposability of a certain kind of semi-norms | *Skordev, Dimiter G.* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | A theorem of Whitney’s type in R2 | *Sendov, Blagovest H.; Takev, Milko D.* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | On linear operators acting in spaces of analytic functions and commuting with Euler's operator | *Raichinov, I.; Raichinov, R. I.* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | On the Pythagorean theorem and the triangle inequality | *Price, G. Baley* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | On generalized orlicz sequence spaces of Fourier coefficients for trigonometric gap series. I. | *Musielak, J.* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | On the strong asymptotic behavior of asymptotically nonexpansive semi-groups in Banach spaces | *Miyadera, Isao* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | On the logarithm of the differential operator | *Mikusinski, Jan* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | An application of the principle of topological induction to the extreme points theorem | *Kounchev, Ognyan* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | The evolution of the areolar derivative analysis in hypercomplex | *Gheorghiev, Gheorghi* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | A solution of the trigonometric moment problem via Tagamlitzki's "Theorem of the Cones" | *Genchev, Todor G.* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | Cauchy sequences and completeness in quasi-metric spaces | *Doitchinov, Doitchin* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | Positive precompact operators | *Cristescu, Romulus* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | A decomposition of integer vectors. II. | *Chaladus, S.; Schinzel, A.* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | Some covering properties of locally univalent functions | *Brannan, David Alexander* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | The gauge invariant currents of the Maxwellian field | *Arens, Richard* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |

**1991 ** | Y. A. Tagamlitzki : A short biographical note | *Skordev, D.; Doitchinov, D.; Genchev, T.; Penkov, B.* | *Institute of Mathematics and Informatics Bulgarian Academy of Sciences* |