There are lots of sources for OER online. Some cover many different topics, some are discipline-specific.
Begin by trying out some of the most well-known sources.
Take a look at this page; it lists a huge amount of OER sources, and you may find one that perfectly suits your subject.
What are the benefits to YOU, if your lecturer uses an OER (Open Educational Resource) textbook or resource in your module?
Remember! ALL the content in MU Library is FREE for you to use while you are studying in MU, so make sure you access the eBooks, eJournals and access to databases in your study. OER provides an alternative, non-traditional way for your lecturer to create customised content for your class, in addition to the millions of free resources in MU Library that you already have access to. Start your search for relevant information on your subject with MU Library's Subject Guides first.