logic - How is $[P \text{ AND } (Q \text{ OR } R)] \text{ IFF } [(P \text{ AND } Q) \text{ OR } (P \text{ AND } R)]$ valid? - Mathematics Stack Exchange
Truth tables - the conditional and the biconditional ("implies" and "iff") - MathBootCamps
The Logical Fallacies: Biconditional
Truth Tables, Tautologies, and Logical Equivalences
GitHub - OpenReasoning/TruthTables: Generate truth tables for logical formulas