,有立方的语言(就是三倍的字符串)或有相等长度的多于四个不同字符的字符串的语言不可以被树-邻接文法所生成。为此,树-毗连文法生成的语言被称为“适度上下文有关语言”。 Jurafsky, Daniel; James H. Martin. Speech and Language Processing. Upper Saddle River
Language Processing with Python. O'Reilly Media. ISBN 978-0-596-51649-9. DanielJurafsky and James H. Martin (2008). Speech and Language Processing, 2nd edition
Language Processing with Python. O'Reilly Media. ISBN 978-0-596-51649-9. DanielJurafsky and James H. Martin (2008). Speech and Language Processing, 2nd edition