Bertold is a prolific writer and his concise and witty legal prose is known for getting to the heart of legal matters. Bertold's major work is a German language commentary on the State aid provisions of the EU Treaty (3rd edition 2012), but he also excels in shorter formats and in editorial style. Recent and upcoming publications include:
- "State Aid Law (Commentary on Articles 107-109 TFEU)", in: Jürgen Schwarze, EU-Kommentar, 4th edition 2019
- "Competition law in the tourism sector" (book chapter, upcoming 2020)
- "Industrial Policy & Merger Control after Siemens/Alstom", in: Antitrust Matters - November 2019, 18 November 2019
- "Commissioner Vestager's Mission Letter - The way ahead", 13 September 2019
- "A landmark EU competition law decision on the restriction of internet sales by authorized resellers of luxury goods", 8 December 2017