TY  - RPRT
TI  - Using the longitudinal Guttman simplex as a basis for measuring growth.
AU  - L M Collins
AU  - N Cliff
PY  - 1990
DO  - 10.1037/0033-2909.108.1.128
UR  - https://pubmed.ncbi.nlm.nih.gov/2200071/
ID  - 2200071
ER  -