71.   Details on arms sales always were -- and remain -- a closely guarded secret.

72.   Exactly what Peggy Salinger plans to say is a closely guarded secret.

73.   His trips are arranged amid massive security and his itinerary is a closely guarded secret, kept even from journalists traveling with him.

74.   His newly designed luge is a closely guarded secret.

75.   Individual choices are guarded secrets until the last minute, but a survey of design watchers suggests that glamour is back in style.

76.   It is difficult to tell how many cloned animals there are worldwide, since many companies keep their successes and failures a closely guarded secret.

77.   It is kept a closely guarded secret and is used to encrypt a message.

78.   Its location is still a closely guarded secret.

79.   Its location remains a closely guarded secret.

80.   Some were presumed destroyed until the Hermitage revealed its closely guarded secret last fall.