add missing commas

CITATIONS.bib

@@ -23,8 +23,8 @@ @inproceedings{Multilingual
   url = {https://storage.googleapis.com/pub-tools-public-publication-data/pdf/35248.pdf},
   year = 2009,
   isbn = {978-1-60558-698-4},
-  date = {2009-07-25}
-  doi = {http://doi.acm.org/10/1145/1577802.1577804}
+  date = {2009-07-25},
+  doi = {http://doi.acm.org/10/1145/1577802.1577804},
   location = {Barcelona, Spain},
 }
 
@@ -33,7 +33,7 @@ @inproceedings{ScriptDetect
   title = {Combined Orientation and Script Detection using the Tesseract OCR Engine},
   booktitle = {MOCR '09: Proceedings of the International Workshop on Multilingual OCR},
   editor = {Venu Govindaraju and Premkumar Natarajan and Santanu Chaudhury and Daniel P. Lopresti},
-  url = {https://storage.googleapis.com/pub-tools-public-publication-data/pdf/35506.pdf}
+  url = {https://storage.googleapis.com/pub-tools-public-publication-data/pdf/35506.pdf},
   year = {2009},
   isbn = {978-1-60558-698-4},
   pages = {1--7},
@@ -47,7 +47,7 @@ @inproceedings{PageLayout
   author = {Ray Smith},
   title = {Hybrid Page Layout Analysis via Tab-Stop Detection},
   booktitle = {ICDAR '09: Proceedings of the 2009 10th International Conference on Document Analysis and Recognition},
-  url = {https://storage.googleapis.com/pub-tools-public-publication-data/pdf/35094.pdf}
+  url = {https://storage.googleapis.com/pub-tools-public-publication-data/pdf/35094.pdf},
   year = {2009},
   isbn = {978-0-7695-3725-2},
   pages = {241--245},
@@ -60,10 +60,11 @@ @inproceedings{TessOverview
   author = {Ray Smith},
   title = {An Overview of the Tesseract OCR Engine},
   booktitle = {ICDAR '07: Proceedings of the Ninth International Conference on Document Analysis and Recognition},
-  url = {https://storage.googleapis.com/pub-tools-public-publication-data/pdf/33418.pdf}
+  url = {https://storage.googleapis.com/pub-tools-public-publication-data/pdf/33418.pdf},
   year = {2007},
   isbn = {0-7695-2822-8},
   pages = {629--633},
   publisher = {IEEE Computer Society},
   address = {Washington, DC, USA},
 }
+