~/RESOURCES/NOTES/
├─ CHAPTER_00
│ ├─ PREDICATES_AND_QUANTIFIERS
│ │ └─
[PDF]│ ├─ LOGICAL_CONNECTIVES
│ │ └─
[PDF]│ ├─ RULES_OF_INFERENCE
│ │ └─
[PDF]│ └─ INFORMAL_FOUNDATIONS
│ └─
[PDF]└─ CHAPTER_01
├─ THE_NATURAL_NUMBERS
│ └─
[PDF]└─ A_THEORY_OF_ARITHMETIC
└─
[PDF]