Frequency Reference - Business Directory https://biz.prlog.org/tag/frequency-reference/ Frequency Reference - Free business directory on PRLog.Org, latest companies listed first. 60 Precise Time and Frequency, Inc https://biz.prlog.org/PTF-Inc/ Ptfinc.com provides GPS Frequency Reference and Time for commercial and military applications. For more inquiry you can call us: 781 245 9090.Wed, 06 May 2015 11:25:19 GMT