What is needed to identify the detailed legal forms covered by the prohibition of ribā?

Degrees of Indication: Ẓāhir, Naṣṣ, Mufassar, Muḥkam and Obscure Expressions

• Rely only on the apparent general sense
• Authoritative explanatory evidence and relevant proofs
• Treat one possible application as conclusive without clarification
• Treat every form of textual indication as absent