BASEES is the UK national learned society for the study of Russia, Eastern Europe and the former soviet union. The main activity of the association is its annual conference
The most important function of COSEELIS is to represent the interests of UK libraries and other information organisations offering services in the field of Slavonic and East European studies
ICCEES is a global consortium of national scholarly associations dedicated to multi-disciplinary scholarly studies of Central and Eastern Europe, including former Soviet countries of Central Asia.
Internet sources need to be treated with extreme caution as quality can be variable. Here are some websites for Church Slavonic studies below. Websites belonging to reputable associations and institutions can be valuable sources of information.