Yes, you are free to create a direct link yourself, although you might want to consider reasons to use eReserves. As well as saving you time, there are two advantages to having the Library create the link. The first is that Library staff will ensure that authentication is taken care of so that your students don’t need to remember to log-in to the Library’s proxy server before going into Waterloo's learning management systems (LEARN). The second advantage is that Library staff will prepare a “persistent” URL. The publisher’s URL for many articles can change from day to day; a persistent URL will ensure that your students get to the right articles quickly and without frustration.
Keep in mind that occasionally a licence prohibits linking. Contact Library Reserves for more information.