Adding References Automatically
There's no need to add books manually. As long as they have an ISBN, Citavi will add the book's information for you. Journal articles also can often be added automatically if they have a DOI name or PubMed ID.
Why Citavi sometimes can't find source information
Sometimes you might enter a DOI name in Citavi but receive the message "Not found in the selected online resources" or the Picker displays the message "No results found for the given criteria". This can happen if the DOI was not found in CrossRef or DataCite. Publishers sometimes register the URL in CrossRef under which the article can be found, but they don't always add the bibliographic information.
If Citavi can't retrieve the bibliographic information for a book, there are a number of possible reasons: the book may have been published in a different language region than the catalogs you selected for the ISBN download or you were searching for a non-academic book in academic library catalogs. Or the book was published by a small press in a limited edition and was not yet cataloged by any library.