(February 16, 2016, 2:04 PM EST) -- BALTIMORE — A mobile advisory consultant may testify about the secondary handset market for cell phone devices and the participation of retail resellers in it, a Maryland federal judge ruled Feb. 10; however, the expert may not opine on whether there have been breaches of contract (Sprint Nextel Corp. v. Simple Cell, Inc., No. 13-617, D. Md.; 2016 U.S. Dist. LEXIS 16017)....