http://www.hueber.de/shared/uebungen/schritte-international/fset.php?Volume=2&Lection=2&Exercise=2&SubExercise=1
http://www.hueber.de/shared/uebungen/schritte-international/fset.php?Volume=2&Lection=2&Exercise=3&SubExercise=1
http://www.hueber.de/shared/uebungen/schritte-international/fset.php?Volume=2&Lection=2&Exercise=4&SubExercise=1
http://www.hueber.de/shared/uebungen/schritte-international/fset.php?Volume=2&Lection=2&Exercise=5&SubExercise=1
