A tip for anyone who finds it convenient for filing
purposes to have proceedings as single PDFs, use
% pdfunite preface.pdf short*.pdf regular*.pdf iwst2022.pdf
to combine the files of the collection into one.
(pdfunite is part of the poppler-utils package.)
Do not be surprised when pdfunite doesn't like the PDF much;
other pdf tools on Ubuntu are also unhappy but not fatally so.