根据给出的参考书目，生成一个写作样本的参考文献。
参考书目：Smith, J. D. (2021). Modern Writing Techniques. New York: Penguin Books.
Smith, J. D. (2021). Modern Writing Techniques. New York: Penguin Books.

样本参考文献：
In his book "Modern Writing Techniques," Smith (2021) discusses various strategies for effective writing in contemporary contexts. The author emphasizes the importance of clear organization and concise language, and provides practical examples and exercises to help writers improve in these areas. Overall, Smith's book offers valuable insights and guidance for anyone seeking to enhance their writing skills.