1 Subjects: “...density threshold theory...”

2 Subjects: “...density functional theory...”

3 Subjects: “...human health, human-nature connection theory...”

4 Subjects: “...graph theory...”

5 Subjects: “...uncertainty reduction theory...”

6 Subjects: “...contingency theory...”

7 Subjects: “...social trust theory...”

8 Subjects: “...critical theory...”

9 Subjects: “...queueing theory...”

10 Subjects: “...protection motivation theory...”

11 Subjects: “...network flow theory...”

12 Subjects: “...item response theory (IRT)...”

13 Subjects: “...fuzzy set theory...”

14 Subjects: “...grounded theory...”

15 Subjects: “...protection motivation theory...”