This is BibTeX, Version 0.99dThe top-level auxiliary file: linear.aux The style file: elsarticle-num.bst Database file #1: linear.bib I was expecting a `,' or a `}'---line 684 of file linear.bib : author={Aristov, Vasili{\u\i}} : Vasilʹevich}, I'm skipping whatever remains of this entry Repeated entry---line 1115 of file linear.bib : @article{sun2017 : , I'm skipping whatever remains of this entry Repeated entry---line 1124 of file linear.bib : @article{li2020unified : , I'm skipping whatever remains of this entry (There were 3 error messages)