1. Optical study of X-ray sources and search for optical counterparts of Gamma-ray burst sources at Sonneberg observatory Creator: Götz, W. Format: bez média and svazek Type: model:article and TEXT Subject: observations, X-ray sources, and Gamma-ray burst sources Language: Czech Description: Some informations about optical study of X-ray sources and search for optical counterparts of Gamma-ray burst sources are given. Rights: http://creativecommons.org/publicdomain/mark/1.0/ and policy:public