Copyright restrictions mean that it's not possible to keep scanned readings visible indefinitely - we're required to remove them at the end of each academic year. We can however roll over any that you plan to re-use (we can send a list of them if needed). If you're updating your own list you don't need to re-request digisations, just contact us readinglists@st-andrews.ac.uk  with the details of the ones to be rolled over.