Assuming you've got the list of what sources you used to do the assignment, it might be worth you submitting that. This does depend on what you're under investigation for. If you missed out in line references but did have a list of books used at the end of the essay or if you've said Joe Bloggs says "whatever it was" but forgot to put the bibliography at the end, then you might be able to get away with a warning. Before submitting your bibliography, find out which referencing system your uni uses (most use Harvard). For an easy to follow referencing guide, google ARU referencing guide. Talk to whoever is doing the investigation to ask if submitting the bibliography will help you. Also contact your SU as they'll be able to help you to get the lowest possible penalty. I would be shocked if referencing errors in a year 1 semester 1 piece of coursework meant you couldn't do your LPC especially if you can get the bibliography handed in asap.