substitute teachers en DPS sues union over sub issue <p>The Detroit Public Schools system has filed an unfair labor practice against the district's teachers' union over a substitute teacher dispute.</p> <p>The president of the Detroit Federation of Teachers issued a letter to some substitutes last month telling them to stop drafting lesson plans, grading students, and holding parent-teacher conferences.</p> Wed, 01 Dec 2010 22:53:32 +0000 Sarah Hulett 424 at