AT&T has assembled a formidable legal team as it seeks to win regulatory approval of its $39 billion acquisition of T-Mobile USA from Deutsche Telekom. A 75-page listing of confidentiality agreements filed with the Federal Communications Commission on Friday reveals the remaining members of its team, and includes details on counsel to other parties opposing the proposed merger.

Last week the FCC hired Wilson Sonsini Goodrich & Rosati antitrust partner Renata Hesse in Washington, D.C., to help oversee its regulatory review of the mammoth deal. The Justice Department’s antitrust division must also approve any merger. Earlier this month the CEOs of both AT&T and T-Mobile USA appeared before Congress to defend their deal, according to The National Law Journal, a sibling publication.

As previously reported by The Am Law Daily, AT&T is receiving antitrust counsel from Arnold & Porter and Crowell & Moring. Corporate work on the deal is being handled by Sullivan & Cromwell. Wilmer Cutler Pickering Hale and Dorr is serving as FCC counsel to AT&T. (Former Wilmer partner Manfred Balz is the top in-house lawyer at Deutsche Telekom, which is seeking to divest itself of T-Mobile USA.)

There are more names to add to the list of law firms connected to the matter, according to the AT&T filing. Sidley Austin partner David Lawson, cochair of the firm’s communications regulatory practice, is advising AT&T, along with antitrust partner David Carpenter, national security and complex litigation partner Richard Klingler, appellate litigation partner C. Frederick Beckner III, and regulatory communications partner Christopher Shenk.

Sidley has been a longtime legal adviser to AT&T, having handled numerous FCC-related litigation and regulatory proceedings for the Dallas-based telecommunications giant. AT&T’s FCC filing states that the company also is receiving regulatory advice from consulting firms The Brattle Group and Compass Lexecon.

Handling matters for AT&T in-house are vice president of federal regulatory affairs Joan Marsh and associate general counsel for FCC and external affairs Gary Phillips and Jack Zinman. AT&T’s general counsel is D. Wayne Watts.

AT&T’s FCC filing also includes a service list of counsel advising various other parties, some of whom are opposed to the T-Mobile USA acquisition.

Sprint Nextel’s has retained Skadden, Arps, Slate, Meagher & Flom communications practice chair Antoinette Bush and Regina Keeney from Washington, D.C.’s Lawler, Metzger, Keeney & Logan for the regulatory fight over AT&T’s T-Mobile USA deal, as we’ve previously reported.

Other firms lining up to advise those opposing completion of the merger include Latham & Watkins. Partner James Barker represents San Diego-based Leap Wireless International, which on Tuesday came out against the AT&T/T-Mobile USA deal on the grounds that it would limit control of the wireless spectrum to a chosen few, according to The San Diego Union-Tribune. Fellow Latham partner Matthew Brill is advising the Rural Carrier Association, another group opposed to the merger.

Bethesda, Md.-based communications firm Bennet & Bennet is advising the Rural Telecommunications Group, which last month asked the FCC to review AT&T’s acquisition of T-Mobile USA and its purchase in December of wireless spectrum licenses owned by Qualcomm. Name partner Caressa Bennet serves as general counsel for the RTG, a D.C.-based industry advocacy group.

Also asking the FCC to combine the two proceedings is a group comprised of companies like Alpheus Communications, Cincinnati Bell Wireless, Level 3 Communications, MetroPCS Communications, Ntelos, PAETEC, and Peerless Networks, which is being represented by Bingham McCutchen telecom partner Jean Kiddoo. (Paul, Hastings, Janofsky & Walker telecom practice leader Carl Northrop is also listed as counsel to MetroPCS, but a firm spokesman says Northrop only introduced the Dallas-based company to FCC officials and is not representing MetroPCS before the regulator. Paul Hastings has also done work for AT&T, and last week MetroPCS expressed concern about the ramifications of an AT&T/T-Mobile USA merger, Bloomberg reports.)

Some parties have yet to take a public stand on the AT&T/T-Mobile USA transaction. Jenner & Block communication chair Samuel Feder and Ropes & Gray antitrust cochair Mark Popofsky are representing Bethpage, N.Y.-based Cablevision Systems, while Greenberg Traurig of counsel Debra McGuire Mercer is advising Miami-based TracFone Wireless, according to FCC filings.

Others are more supportive. Patton Boggs partner Matthew Berry is advising the Communications Workers of America, a trade union advocating for approval of AT&T’s T-Mobile USA buy.

This article originally appeared in The Am Law Daily.