fix bibtex braces

Author: NathanielF

examples/references.bib

@@ -457,9 +457,7 @@ @book{kline2023principles
 	year         = 2023,
 	publisher    = {Guilford Publications},
 	series       = {Methodology in the Social Sciences Series},
-	isbn         = 9781462551910,
 	url          = {https://books.google.ie/books?id=t2CvEAAAQBAJ},
-	lccn         = 2023000442
 }
 @article{koren2009matrixfactorization,
   author        = {Koren, Yehuda and Bell, Robert and Volinsky, Chris},
@@ -879,12 +877,10 @@ @inproceedings{vanderplas2012astroML
 @book{vehkalahti2019multivariate,
 	title        = {Multivariate Analysis for the Behavioral Sciences},
 	author       = {Vehkalahti, K. and Everitt, B.S.},
-	year         = 2019,
+	year         = {2019},
 	publisher    = {CRC Press, Taylor \& Francis Group},
 	series       = {A Chapman \& Hall book},
-	isbn         = 9780815385158,
 	url          = {https://books.google.ie/books?id=LX97uwEACAAJ},
-	lccn         = 2018041904
 }
 @online{vehtari2022Birthdays,
   title         = {Bayesian workflow book - Birthdays},