Possible Clues:

• 'My Antonia' author
• "O Pioneers!" author
• Constructor (from Thrace) of Alexander's Bridge
• 'One of Ours' Pulitzer-winning author
• "One of Ours" Pulitzer-winning author
• Willa who wrote 'My Ántonia'
• "My Antonia" novelist
• 'My Antonia' writer
• Novelist Willa
• ''O Pioneers!'' author