## 2 Literature Review and Related Work
### Accounting, AIS and ERP and DLT  
The accounting process (Figure 1) is an essential part of any business, principally because enforced by law worldwide. All companies are required to prepare and keep the books and accounting records required by civil, fiscal, corporate and labour regulations [34]. The accounting books that companies must keep vary according to the type and size of the business. The mandatory records and accounting books are those documents that the legislation requires to draw up and support to: (a) represent and demonstrate the individual business documents, both from a quantitative and monetary point of view; (b) allow a clear and truthful representation of the company's equity, financial and economic situation [52]. The correct preparation and conservation of accounting books is an indispensable element for any company. In this sense, all companies are required to keep: (a) the journal, that is, the book in which all management operations are recorded in chronological order (purchases, sales, collections, payments, etc.); (b) the ledger, relating to all the ledger accounts that are used during the accounting entry operations [34].  
It also ensures the measurement of the business financial results. Therefore, understanding and matching the accounting needs is vital to avoid compromising the company reputation, going concern, and stakeholders' trust [12; 53].  
Any transaction that the company performs with external entities should be recorded in the bookkeeping system (FI module) as an invoice (expenses or revenues), a payment, a payable, or a receivable, and further processed for other internal purposes (i.e., inventory management, quality, production, logistics) [54; 55]. Therefore, a direct link between the AIS modules and other ERP modules can be demonstrated. For example, the same transaction, let us assume a purchase, affects the general ledger and general journal accounting books in the administration department and other departments like production, quality, supply chain, logistics, sales, marketing, and so forth. Given the potentially significant benefits in auditing and accountability, some attempts have been made to implement blockchain-based accounting systems. Nevertheless, the literature is not much developed, especially concerning theoretical applications (i.e., e-procurement etc.). Furthermore, given the  
Figure 1: The Accounting Process.  
importance of a fair financial disclosure, directly related to the public trust in the financial markets, standardisation in accounting is ensured by very detailed regulations, laws, accounting standards (i.e., IAS/IFRS, US GAAP), XBRL taxonomies [56; 57].  
A notable example is e-invoices (which are rapidly replacing paper-invoices worldwide). However, despite the countless advantages they generate, only the enforcement of national (local) revenue agencies and governments led to their universal use in B2B, B2G, and B2C transactions [58; 59; 60]. Therefore, the expectations can be similar for implement blockchain-integrated accounting information systems. Thus, revenue agencies and public authorities policies and regulations should be considered essential in the design and enforcement of shared, public, permissioned distributed ledger platforms. The ERP vendors should follow and adjust their systems to make them compliant with the public blockchain platform.