31.   The sometimes lethal practice has prompted tougher laws, public awareness campaigns, and even the deployment of battlefield technology that can pinpoint the source of gunfire.

32.   The system, an offshoot of technology used in the Gulf War, uses sound sensors to pinpoint the source of gunfire and broadcasts the coordinates to police.

33.   They were seeking to pinpoint the source of elevated nitrate levels in downstream reservoirs.

34.   At issue are radar systems that can pinpoint the source of incoming artillery fire.

35.   They will be protected by anti-sniping patrols equipped with thermal-detection devices to pinpoint the source of any fire.

36.   It was impossible to pinpoint the source.

37.   Officials were still trying to pinpoint the source of the oil spill.