Update paper.bib

In response to editor review

Author: lmoresi

docs/joss-paper/paper.bib

@@ -196,7 +196,6 @@ @article{knepleyAchievingHighPerformance2013
   langid = {english},
   keywords = {Computer Science - Computational Engineering Finance and Science,Computer Science - Mathematical Software,No DOI found},
   annotation = {9 citations (Semantic Scholar/arXiv) [2022-04-21]},
-  file = {/Users/lmoresi/Zotero/storage/7H2PC7HT/Knepley et al. - 2013 - Achieving High Performance with Unified Residual E.pdf}
 }
 
 @book{loggAutomatedSolutionDifferential2012,
@@ -350,7 +349,7 @@ @book{zienkiewiczFiniteElementMethod2013
   edition = {Seventh edition},
   publisher = {Elsevier, Butterworth-Heinemann},
   address = {Amsterdam},
-  doi = {10.1016/b978-1-85617-633-0.00019-7},
+  doi = {10.1016/C2009-0-24909-9},
   isbn = {978-1-85617-633-0},
   lccn = {TA640.2 .Z5 2013},
   keywords = {Engineering mathematics,Finite element method,Fluid dynamics}