Dr. Jolien A. Helsel Department of Economics If you don't have Adobe Acrobat reader installed on your computer (you will need this application to read some of the files on this site), you can download it here. Select your course below: Principles of Microeconomics (Spring 2009) - MWF 1:00 pm Principles of Microeconomics (Spring 2009) - MWF 2:00 pm Principles of Microeconomics (Spring 2009) - T Th 8:00 am History of Economic Thought (Spring 2009)