1. The Constitution (the fiscal constitution: Arts 59-60's fiscal powers-and-sharing (the verified texts); the parliament's money-powers (the budget-and-taxation faces); the AG's audit (Art 240-ish's verified frame)).
2. The statutes (the tax acts (U5); the budget-and-appropriation acts; the IGFA Act 2074).
3. The delegated instruments (the finance minister's rules; the departmental directives; the rates' notifications).
4. The international layer (the WTO's tariff bindings; the DTAs (the double-taxation agreements' line); the IFIs' conditions).
5. The jurisprudence (the fiscal cases — the tax disputes' line (the prescribed cases' cluster)).