updates

doc/src/tut/main_sketcher.do.txt

@@ -1,5 +1,5 @@
 TITLE: Using Pysketcher to Create Principal Sketches of Physics Problems
-AUTHOR: Hans Petter Langtangen at Center for Biomedical Computing, Simula Research Laboratory and Department of Informatics, University of Oslo
+AUTHOR: Hans Petter Langtangen at Center for Biomedical Computing, Simula Research Laboratory & Department of Informatics, University of Oslo
 DATE: today
 
 __Abstract.__