Merge remote-tracking branch 'upstream/3.4' into merge-3.4

doc/opencv.bib

@@ -850,12 +850,12 @@
   journal = {IEEE Transactions on Robotics and Automation},
   title = {Robot sensor calibration: solving AX=XB on the Euclidean group},
   year = {1994},
+  month = oct,
   volume = {10},
   number = {5},
   pages = {717-721},
   doi = {10.1109/70.326576},
-  ISSN = {1042-296X},
-  month = {Oct}
+  issn = {1042-296X}
 }
 @inproceedings{PM03,
   author = {P{\'e}rez, Patrick and Gangnet, Michel and Blake, Andrew},
@@ -1051,12 +1051,12 @@
   journal = {IEEE Transactions on Robotics and Automation},
   title = {A new technique for fully autonomous and efficient 3D robotics hand/eye calibration},
   year = {1989},
+  month = jun,
   volume = {5},
   number = {3},
   pages = {345-358},
   doi = {10.1109/70.34770},
-  ISSN = {1042-296X},
-  month = {June}
+  issn = {1042-296X}
 }
 @inproceedings{UES01,
   author = {Uyttendaele, Matthew and Eden, Ashley and Skeliski, R},