Prebyornis Papers Prove Problematic

The issue with finding papers today has not so much been that there are no papers that mention or discuss Presbyornis available so much as there are not very many that are specifically about Presbyornis on account, in part, due to the fact that most of the genus and species specific papers were written long before the internet and scanners were available. There are a number of papers which reference or discuss Presbyornis, such as this paper on evolutionary radiation during the Cretaceous, which give a lot of good insight into the genus and species. There have been new fossils found which are compared to Presbyornis or belong in its family and the papers on those are available. The Olson and Feduccia paper of 1980 is a paper I wish I could find to share on here, instead, all I have is an image from the paper: