This question comes up again and again and is well worth its own blog post. Our answer could be: if it is a lecture Powerpoint, something on a VLE, or something the tutor created themselves, then look at the bit of the Cite Them Right Online site under Comms/Public Communications, and follow the advice given.
A better answer might be: approach with caution.
Imagine you are the lecturer, faced with a pile of assignments to mark. You are excited to see what each student has been reading; what has influenced the students’ thinking about the topic or assignment question; reading about the latest research each student has found, read and interpreted in the context of the task set. Instead, you are faced with assignments which reference your own handouts, lecture notes and Blackboard materials, right back at you. Perhaps the student hasn’t treated the lecture materials as the springboard for wider reading and research after all!
So branch out a bit- check out your resource list, search for info on Library search or take a look at the range of resources specifically available in your subject area. Then you can impress your lecturer with all the stuff you've learned outside the classroom and hopefully get better grades.