Rhinoceros is part of a series of plays that feature the character Berenger: others include The Killer and Exit the King. Consider also Ionesco's other plays, among them Hunger and Thirst and The Bald Soprano.
Consider critic Martin Esslin's book The Theatre of the Absurd, and the work of the other playwrights featured in it, such as Samuel Beckett's Waiting for Godot or Jean Genet's The Maids.
Consider Ionesco's autobiography Present Past Past Present.