**MATHEMATICS** | | |

N. Elez | Equations related to the boundary operator in a topological space | 5 |

V. O. Chiboka | The Bryant - Schneider group of an extra loop | 9 |

Sever Dragomir | On some integral inequalities for convex functions | 21 |

Daniel A. Romano | Some results on quotient coideal of coideal which is the union of primary coideals | 27 |

Zdravko Starc | Exponential estimates for solutions of second order linear ordinary differential equations | 35 |

Jovanka Nikić | Properties of the Nijenhuis tensor of almost Hermite manifold | 41 |

Boško Damjanović | Interior boundary value problem for polyanalytic functions in simple connected regions | 51 |

Nikola Rosić | Some properties of the particular solutions of differential equations | 59 |

Dragić Banković | Solutions of k-valued equations | 69 |

Ivan Gutman | On the energy of quadrangle-free graphs | 75 |

Olga Miljković | Simulation using concepts of artificial intelligence | 83 |

**PHYSICS** | | |

Jovanka Živojinov Srboljub Stamenković Vladimir Ristić | Determination of partition function for solid mercury in the temperature interval from 0 to 8K_{ } | 95 |

**CHEMISTRY** | | |

Ivan Gutman Murlidhar V. Kaulgud Vijau H. Chitgopkar | Wiener numbers of non-periodic polymers | 105 |

**BIOLOGY** | | |

Milić Matović Ljiljana Vujković Aca Marković | Study of some relict species in the north-west part of the Balkan peninsula - a contribution to protection of biodiversity | 115 |