A new issue of Mathematical Thinking and Learning has appeared: Volume 11, Issue 4, 2009. The issue contains three research articles (along with an editorial by Lyn D. English and a book review):

• Learning Mathematics via a Problem-Centered Approach: A Two-Year Study, by Candice L. Ridlon 
• Efficacy of Different Concrete Models for Teaching the Part-Whole Construct for Fractions, by Kathleen Cramer; Terry Wyberg 
• Reasoning-and-Proving in School Mathematics Textbooks, by Gabriel J. Stylianides