You can choose a reference management tool e.g.  Endnote, Zotero, and Mendeley. University of Helsinki offers Endnote. Zotero and Mendeley have a free version available.

The Overleaf Professional license is available to members of the hy-mltdk-allstaff email list and students whose primary study right is at the Faculty of Science. Login must be with the helsinki.fi address. If you have been using some other email address in your current overleaf account, you must change to the helsinki.fi address if you wish to get the get the features of the Professional licence. 
Access Professional account at https://www.overleaf.com/edu/helsinki