| Burroughs Truth-Function Evaluator | ⊕ 1954 | ↓ ↑ ⊕ Experimental and other | Predicate | ⊕ United States | Logical evaluator system |
| PL/CV | ⊕ 1975 | ↓ ↑ ⊕ Specialised Languages | Predicate | ⊕ United States | Verifying logical dialect of PL/CS |
| PL/CV2 | ⊕ 1982 | ↓ ↑ ⊕ Specialised Languages | Predicate | ⊕ United States | Verifying logical dialect of PL/CS |
| SRL | ⊕ 1990 | ↓ ↑ ⊕ Specialised Languages | Predicate | ⊕ United States | Logic programming language |