11.   Could be what track people called the Roger Bannister effect, the shattering of the mental barrier of the four-minute mile.

12.   Ellroy recounts how he and Stoner tried to track down people who had known his mother and tried to reconstruct the day of her death.

13.   Finally, in March, both women agreed to talk about their sexual partners, and the investigator began the painstaking task of tracking those people down.

14.   First came the research, gathering papers and letters and tracking down people she had not seen in years.

15.   For automatic operation, Roboguard is fitted with infrared sensors that allow it to track people as they move.

16.   Governments could track innocent people, while criminals hacking into the system could use the signals to home in on targets.

17.   He said that it was relatively easy to track people producing counterfeit products within a specific region like North or South America or a single country.

18.   Hill, an amateur musician, said he had designed the program to help artists track people distributing their music without permission.

19.   Just how these photographers track down the right people is a mystery.

20.   Nor is the agency quickly able to track people coming in and out of the country, since its antiquated system still records such information in paper files.