Again, 2 DDTC Professionals Contribute to Global Tax Publication!
VIENNA, DDTCNews – The annual Klaus Vogel Lecture was held on 2 October 2026 at WU Campus, Vienna, Austria. The event is organised specifically to honour the academic dedication of the late Prof. Klaus Vogel (1930–2007), a highly respected figure and expert in international tax law, renowned above all for his thinking and seminal reference work on tax treaty interpretation.
This annual event has become one of the most prestigious academic forums in international taxation, bringing together experts, practitioners and academics from across the globe. This year, the main theme was Federal Fiscal Solidarity in the European Union, presented by Prof. Ruth Mason, Professor of Law and Taxation at the University of Virginia School of Law.
At the event, academic works by two DDTC professionals, namely Senior Tax Expert, CEO Office DDTC Dawud Abdul Qohhar Lubis and Tax Expert, CEO Office DDTC Abiyoga Sidhi Wiyanto, entered the international arena, with their theses published in a book entitled Taxation of Services.
The official launch of the book formed part of the opening agenda of the Klaus Vogel Lecture 2026. Within the programme, that session was delivered by Dr. Jürgen Romstorfer and Mag. Severin Schragl. Meanwhile, Prof. Michael Lang, as Academic Director of the LL.M. Programme in International Tax Law at WU, attended to deliver a welcome address and to present the book.
Photo caption: the book entitled Taxation of Services, published by Linde Publishing, was introduced for the first time at the 'Klaus Vogel Lecture 2026' held at the Vienna University of Economics and Business (WU), Friday (2/10/2026).
Published by Linde Verlag, Taxation of Services is the 151st volume in the Series on International Tax Law. The 790-page book is edited by Romstorfer and Schragl and examines the taxation of services through 29 sub-topics.
Market Jurisdiction Taxing Rights and Digital Services Tax
In their introduction, the two editors explain that the practice of writing theses on a shared theme and subsequently publishing them in a book has become a tradition of the LL.M. programme at WU. For the 2025/2026 cohort, that theme focuses on the taxation of services from various international tax law perspectives.
In his paper entitled 'Digital Services Taxes: Contingency Plans for the Failure of Pillar One Amount A', Dawud examines the digital services tax (DST) as a policy option in the event that Pillar One Amount A fails to materialise. His analysis compares both approaches in terms of revenue, multilateral and unilateral mechanisms, consumer welfare, and their respective advantages and disadvantages.
Meanwhile, in his paper entitled 'Taxing International Services: A Market Jurisdiction's Perspectives', Abiyoga highlights the limitations of a taxation approach premised on physical presence at a time when business activities are becoming increasingly digitalised.
In today's environment, companies can serve consumers in a given country without needing to maintain an office or a permanent establishment (PE) there, making the allocation of taxing rights a significant issue. The paper also examines demand-based approaches and unilateral policy options in the taxation of international services.
By way of further background, prior to Taxation of Services, several other DDTC professionals have also contributed to international tax books. One such example is DDTC Founder Darussalam in the book A Global Analysis of Tax Treaty Disputes.
Several other international tax books that also feature contributions from DDTC professionals include Transfer Pricing Law Review, The Tax Disputes and Litigation Review, Implementing Key BEPS Actions: Where Do We Stand?, Controlled Foreign Company Legislation, The Implementation and Lasting Effects of the Multilateral Instrument, Justice, Equality and Tax Law, Mandatory Disclosure Rules, and Mobility of Work. There are also various other international publications.
A number of the international publications featuring contributions from DDTC professionals have also emerged from learning processes through coursework, training, or global-level conferences. The participation of DDTC professionals in these various activities forms part of the Human Resource Development Programme (HRDP).
Each year, through the HRDP, DDTC awards bond-free scholarships to its professionals to participate in various tax competency development programmes. These opportunities encompass training through to formal undergraduate and postgraduate education at leading institutions and universities, both domestically and abroad.
With regard specifically to overseas study, DDTC professionals have to date pursued their learning in 20 countries. The HRDP serves as a tangible expression of one of DDTC's missions — investing in its human resources. That commitment simultaneously underpins DDTC's vision of becoming a tax institution grounded in research, technology, and knowledge that upholds high and sustainable standards. (kaw)