282nd Symposium of the International-Astronomical-Union, Tatranska Lomnica, Slovakya, 18 - 22 Temmuz 2011, ss.85-86
This paper presents the results of the analysis of (O-C) diagrams of four eclipsing variables. The diagrams are based on times of minima collected in the Cracow database, which contains times of minima found in the literature, from observations at Mt. Suhora and Ulupinar Observatories, or determined using publicly-available photometric surveys (NSVS, ASAS etc).