51.  So he started knocking on doors with his original material but no credentials.

52.  Some drivers literally go knocking on doors.

53.  Staff members no longer have to routinely knock on doors or keep cameras on residents to monitor movements.

54.  The character was charming, but a year of knocking on doors of potential funders was so fruitless he nearly gave up.

55.  The first time I met Beam she was out knocking on doors to find space in the valley for her group after Art Space lost its building.

56.  The lawyers kept knocking on doors of former neighbors and friends.

57.  The key to growth is not that Vasquez went out to neighborhoods and knocked on doors, although he was not beyond that.

58.  The momentum has sent many developers knocking on doors.

59.  The thing is, why is the Red Cross knocking on my door?

60.  Then, when she knocked on his hotel-room door one night in Houston, he decided it was time to call NFL security.