Error in adding a column based on one column(from an other file)

[Na_LIU]

I want to add column based on one column,
I typed the expression following:
cell.cross('scopus REFERENCES
csv','EID').cells['References'].value[O]

and the cell.cross showed following:
Error: Unable to find project with name: scopus REFERENCES
csv
why did it happen? I opened the two files at the same time.

[Na_LIU]

and it showed
Error: Multiple (3) projects found with name: scopus REFERENCES csv