REX usually uses the  ISO-standard for translitteration for the CATALOGUING and DISPLAY of materials published in the Cyrillic alphabet.
Examples of ISO-transliteration: Šajtanov (Шайтанов), Čudakov (Чудаков), Mandel'štam (Мандельштам), Dostoevskij (Достоевский), žizn' (жизнь), Zoščenko (Зощенко), Chruščëv (Хрущёв).
Exception: Books that are currently in order may be transliterated according to other systems. However, when they enter The Royal Library collection, they will be changed to the ISO-standard.

When SEARCHING in REX, the English/American transliteration is used. I.e. Shajtanov, Chudakov, Mandelshtam, Dostoevskij, Zhizn, Zoshchenko, Chrushchev.