make it more obvious you can enter a custom source

[nicoalee]

It's not super obvious to users that they can type freetext and enter their own source when importing a file (bibtex, endnote) into curation. The solution to this might be as simple as adding placeholder text "Type to add/create your own source".

[jdkent]

Adding the option "My Local Reference Manager" as Adam said would also make it clear you can upload your own bibtex file. (And they may be the most common use case)