This is the 14376th most frequent Russian word.
отобраны
"Selected" or "taken away," depending on context.
In this sentence, 'отобраны' is used in the past passive voice, indicating that the selection process of the books was carried out by someone, i.e., the experts.
Книги для библиотеки были отобраны экспертами.
The books for the library were selected by experts.
Here, 'отобраны' again shows past passive voice, describing the act of selecting team players that was done according to a strict procedure.
Игроки команды были отобраны через тщательный процесс.
The team players were selected through a thorough process.
In this case, 'отобраны' reflects the outcome of a selection process where the jury chose the most outstanding works for the exhibition.