11.   One source close to the investigation explained how investigators have been able to pinpoint the source of the explosion.

12.   Pinpointing the source of nitrates is guesswork, short of expensive testing that state regulators have yet to do.

13.   Pinpointing the source of the organisms often is impossible, since they occur naturally in the body.

14.   Senior Pakistani officials said they were seeking assistance from U.S. experts to help monitor the communications and pinpoint their source.

15.   The agency also hopes to use the technology in the future to help pinpoint the sources of air pollution and acid rain.

16.   The outbreak began in early August, but the low number of cases made it difficult for health officials to recognize the outbreak and then pinpoint its source.

17.   The researchers cannot yet pinpoint the source of the pollution within Asia.

18.   The term was being used the day after the election, although etymologists have not pinpointed its source.

19.   There are two basic ways to pinpoint the source of cellphone calls.

20.   Young used his electronic gear to pinpoint the source to the apartment complex.