• The independence of the auditor
• The determination of materiality by auditors
• Reporting by auditors

• Association of German University Teachers, there in the Scientific Commission for Accounting (WK-RECH)(Link)
• Chamber of Public Accountants (WPK) (Link)
• Institute of German Certified Public Accountants (IDW) (Link)
• Tax Forum Trier e.V.(Link)
• Editorial Board of the journal Management Review Quarterly (MRQ)(Link)

Monograph:

• Widmann (2019): Das Prüfungshonorar des Abschlussprüfers - Eine Analyse der Preissetzung vor dem Hintergrund der EU-Reformen zur Abschlussprüfung, cp. dissertation University of Trier, Hamburg.

Articles in (scientific) journals:

• Wolz/Henrich/Widmann (2015):  The external rotation requirement: curse or blessing? - A study of the target achievement curve of the Audit Reform Act (AReG) for German capital market-oriented  companies - , in: KoR-IFRS 12/2015, pp. 622-628 
• Widmann/Wolz (2019): Audit quality in the area of conflict between joint audits and external rotation - Can the different implementation measures of the EU Member States really be expected to lead to higher quality audits in the future?, in: ZCG, 14th Vol. 5/19, pp. 222-229
• Widmann/Wolz (2019): The so-called fee cap for permissible non-audit services of the auditor - An outlook on the first-time consideration of Art. 4 (2) EU-AprVO, in: ZCG, 14th Vol., No. 6/19, pp. 264-271
• Widmann/Wolz (2020): The external mandatory rotation of the auditor - A review of global regulations, in KoR-IFRS, 20th Vol., Issue 6/20, pp. 281-286
• Widmann/Wolz (2020): The duration of the audit relationship in an EU comparison - Do the implementations of the nation states on the external mandatory rotation of the auditor fulfill their purpose? -in WP-Praxis, 9th vol., issue 5/20, pp. 136-140
• Widmann/Wolz (2020): The influence of the duration of the mandate on the audit fee - results of an empirical study, in ZCG, 15th vol., issue 4/20, pp. 177-182
• Widmann/Velte (2020): The use of big data in the context of the annual audit - Selected points of contact in the course of analytical audit procedures, in WP-Praxis, 9th vol., issue 7/20, pp. 198-203
• Widmann/Velte (2020): Contestable legal transactions by the insolvency administrator - analysis and assessment of selected audit procedures, in: WP-Praxis, 9th vol., issue 12/20, pp. 361-35
• Widmann/Follert/Wolz (2021): What is it going to cost? Empirical evidence from a systematic literature review of audit fee determinants, in: Management Review Quarterly, 71st Vol., pp. 455-489
• Drewes/Follert/Widmann (2021): The Wirecard case and the consequences - legal economic analysis of a German legislative proposal, in: ZCG, 16th vol., issue 2/21, pp. 72-79
• Widmann/Follert/Wolz (2021): On the Political Decision of Audit Market Regulation - Empirical evidence of audit firm tenure and maximum durations within the European Union, in: Economies, 9. vol.
• Widmann/Wolz (2021): Is the tightening of the external rotation obligation by the FISG really expedient? A comparative analysis of data from the audit markets in the USA and the EU, in: ZCG, 16. vol. 4/21, p.174-181
• Widmann/Nickels/Wolz (2021): On the determination of the materiality threshold by the auditor - results of a survey of the German profession compared to findings from the UK, in: WPg, 74th Vol., No. 16/21, pp. 991-997
• Widmann (2022): Life Cycle Costing, in: WP-Praxis, 11th Vol., Issue 1/22, pp. 32-35
• Widmann/Nickels (2022): Determination of materiality thresholds - results of a case study in the German profession, in: WP-Praxis, 11th vol., issue 3/22, p. 89 - 95
• Widmann (2022): Performance measurement and remuneration, in: WP-Praxis, vol. 11, issue 5/22, pp. 186-188
• Widmann/Wolz (2022): On the internal rotation of the responsible audit partner - Assessment of the arguments for shortening the maximum term, in: ZCG, 17th Vol., No. 3/22, pp. 123-128
• Widmann/Wolz (2022): The internal rotation of the responsible audit partner - A review of worldwide regulations, in: KoR, 22nd Vol., Issue 7-8/22, pp. 311-315
• Schmitz/Widmann (2022): The determination of materiality in the shadow of the Corona pandemic - An analysis of reported benchmarks and thresholds in the UK, in: ZCG, 17th Vol., No. 4/22, pp. 177-184
• Widmann/Tausch-Nebel (2022):   On dealing with other own work capitalized in the cash flow statement in accordance with DRS 21 - A review of the relevant commentaries on the HGB, in: DK, 16th vol., pp. 465-471
• Widmann (2023): Data analysis - Benford's law, in: WP-Praxis, 12th Vol., No. 6/23, pp. 186-188
• Tettenborn/Widmann (2023): On the assessment of the criterion of future economic benefit as a prerequisite for the recognition of internally generated intangible assets, in: IRZ - Zeitschrift für internationale Rechnungslegung, Vol. 18, Issue 7-8/23, pp. 323-327
• Freichel/Widmann/Apelganz (2023): Account models for commercial partnerships in the context of the corporate taxation option, in: DStR, 61st Vol., No. 31/23, pp. 1734-1742
• Freichel/Widmann/Henrich (2023): Method-specific design freedoms in the accounting of direct commitments in the commercial balance sheet, in: StuB, 22nd Vol., No. 16/23, pp. 641-649
• Freichel/Widmann(2023): Sample sizes depending on the defined (tolerance) materiality, in: WP-Praxis, 12th vol., pp. 284-289.
• Freichel/Widmann (2024): Refusal or denial of the endorsement? Differentiations to section 322 (1) no. 3 and no. 4 HGB and reform proposals, in: WP-Praxis, 13th vol., pp. 11-17
• Widmann/Odenthal (2024): Regression analysis as an analytical audit procedure - implementation options using MS-Excel and ChatGPT+ based on a case study, in: WP-Praxis, 13th vol., pp. 47-53
• Freichel/Widmann (2024): "Unusual" or "usual", that is the question - On the disclosure of depreciation on current assets in accordance with Section 275 (2) no. 7 letter b HGB, in: DStR, 62nd vol., issue 11/24, pp. 628-636

Articles in commentary volumes/databases (with annual updates - most recently 02.02.2024):

• Widmann/Haddad (2024): IFRS 17 - Insurance Contracts, in: Thiele/von Keitz/Brücks (eds.), International Accounting Law

• Wolz/Widmann (2020): Auditor rotation, in: NWB InfoCenter

• Wolz/Widmann (2020): Joint Audits, in: NWB InfoCenter

• Wolz/Widmann (2020): Audit committee, in: NCA InfoCenter

• Wolz/Widmann (2020): Classification of the income statement, in: NWB InfoCenter

• Wolz/Widmann (2020): Appropriation of earnings, in: NWB InfoCenter

• Wolz/Widmann (2020): Strict lower of cost or market principle, in: NWB InfoCenter

• Wolz/Widmann (2020): Consolidated financial statements and interest barrier, in: NWB InfoCenter

• Wolz/Widmann (2020): Consolidated financial statements and consolidated tax group, in: NWB InfoCenter

• Wolz/Widmann (2020): Accounting for land and parts of land, in: NWB InfoCenter

• Wolz/Widmann (2020): Contingent liabilities/liabilities, in: NWB InfoCenter

• Wolz/Widmann (2020): Revenue recognition, in: NWB InfoCenter

• Wolz/Widmann (2020): Disclosures on off-balance sheet transactions, in: NWB InfoCenter

• Wolz/Widmann (2020): Extraordinary expenses and income, in: NWB InfoCenter

Contributions to commemorative publications/editorials:

• Widmann/Matheis/Wolz (2024): On the influence of engagement duration on audit quality, in: von Ahsen/Schiereck/Wolz (eds.) (2024), Quick Notes on Accounting - Festschrift on the 65th birthday of Reiner Quick, pp. 213-236

Other publications:

• Follert/Widmann (2020): Politischer Aktionismus: Zum Referentenentwurf (Entwurf eines Gesetzes zur Stärkung der Finanzmarktintegrität) aus Sicht der Neuen Politischen Ökonomie, in: Wirtschaftliche Freiheit - Das ordnungspolitische Journal 2020
   

Interviews:

• WPK Magazine 3/2022: Young professionals of tomorrow(Link)

Press releases:

• Informationsdienst Wissenschaft: Are the tightening of the regulation of auditors more than political actionism?(Link)