TY  - RPRT
TI  - A tetrad test for causal indicators.
AU  - K A Bollen
AU  - K F Ting
PY  - 2000
DO  - 10.1037/1082-989x.5.1.3
UR  - https://pubmed.ncbi.nlm.nih.gov/10937320/
ID  - 10937320
ER  -