itunesu - recover lost files

A coworker was is a "technical training" course bucket, that I believe had about 12 recordings in it. She said ".... was attempting to add a file to the bucket on the Technical Trainings tab and inadvertently made everything disappear. I thought that I could change the tab setting to simple to allow me to upload the file and then switch back to smart but I thought WRONG!"

I cannot find any sort of recovery options, can someone please help me with this? Thank you.