I am sure that you are aware that for the copyrighted material that you wish to use, you need to take permission from the owner of the copyright. So, according to me, it is always good and feasible to refer to Open Educational Resources (OER), otherwise, one may violate copyrights of the resources that are shared. Further, it is a good practice to provide appropriate credit to the creators of open resources and abide by the Creative Commons licensing terms.
You must have noticed that in this course, for every external resource that is provided to us, appropriate attribution has been given to its creators.
Daisy Wadhwa
(Moderator)