What is a Primary Source? The American Library Association describes them as:
In dance, some of the more common primary sources one might encounter include a recording of a performance, pictures of a dancer, letters written by a figure in dance, and newspaper reviews of a performance; however, this is certainly not a comprehensive list of all possibilities.
What is a Secondary Source?
Primary sources are oftentimes located in librarie's Special Collections and Archives departments. These collections generally need to be accessed through finding aids, a listing of materials in a particular collection. Finding aids, searchable in catalogs such as Library Search, will normally give an overview of the collection and its organization, but doesn't list every single item. This means that you need to think where a particular item that interests you would be located and then request the folder or box listed in the finding aid.
UCI Libraries has excellent special collections related to dance and other performing arts. Visit the UCI Special Collection page of this Dance Guide for more information.
Many other libraries offer special collections related to dance and performing arts. Visit the Other Special Collections page of this Dance Guide for more information.
A picture from the Eugene Loring papers in UCI Libraries Special Collections.