which I focus on during research:
— names, Eastern Europe is a multilingual and multicultural region, so it is important to consider all possible forms of a personal name, patronymic and surname;
— dates, they helping identify a person and giving time frames for facts and events;
— religion and social group, because each community had its own history which provides clues for the research;
— places of residence give us location frames and able to prove relationships between residents;
— occupation and place of work, despite possible biases, could outline persons portrait, their motives and reasons;
— accuracy of facts and possible ambiguities, to highlight weak points of the evidence base.