ANDRZEJ KOSTRZEWSKI: The scientific output of Professor Bogumil Krygowski on the 100th anniversary of his birth (1905-1977)ROBERT BOGDANOWICZ: Analysis of temporal changes in nitrogen transport of the Vistula River in relation to seasonal and long-term variations in river dischargeMlCHAL FARYŚ: Influence of soil salinity on soil bidirectional reflectance observed in Central MexicoMARIA GÓRSKA: Sediments of the Odra Lobe in the light of selected textural and mineral analysesALFRED KANIECKI: Methodological problems pertaining to the study of transformations of water relations in urban areasMAŁGORZATA NITA, KRZYSZTOF WÓJCICKl: Record of Holocene vegetation changes against a background of environmental conditions in the Kłodnica valley (southern Poland)RENATA PALUSZKIEWICZ, RYSZARD PALUSZKIEWICZ: Lithofacies differences in proglacial lake sediments: an example of the Pyrzyce and Zlocieniec proglacial lakes (West Pomerania)ALOJZY WOŚ: Outline of features of the climate of Poznan in the second half of the 20th century in the light of average annual values of selected weather elementsDARIUSZ WRZESINSKI: Changes of the hydrological regime of rivers of Northern and Central Europe in various periods of the North Atlantic Oscillation