51.  It is a very unusual case.

52.  It was an unusual case since bill signings are rarely, if ever, the grist for political spats.

53.  Nike is an unusual case.

54.  Sacks has gained a reputation for uncovering unusual medical cases.

55.  The sisters hope their extremely unusual case brings attention to this little-known but gentler form of breast reconstruction.

56.  The unusual cases were first observed in mid-October.

57.  What happened next has become the focus of an unusual federal kidnapping case.