PULLEIN CHRISTINE. (2019). THE MYSTERY OF SPITEFUL LETTERS (2014 Ed.). EGMONT BOOK PUBLISHERS LTD.
芝加哥风格引文PULLEIN CHRISTINE. THE MYSTERY OF SPITEFUL LETTERS. 2014 Ed. LONDON: EGMONT BOOK PUBLISHERS LTD, 2019.
MLA引文PULLEIN CHRISTINE. THE MYSTERY OF SPITEFUL LETTERS. 2014 Ed. EGMONT BOOK PUBLISHERS LTD, 2019.
警告：这些引文格式不一定是100％准确.