TY  - RPRT
TI  - The Marbles test. A test for small groups.
AU  - R J Usandivaras
AU  - W R Grimson
AU  - H Hammond
AU  - E Issaharoff
AU  - D Romanos
PY  - 1967
DO  - 10.1001/archpsyc.1967.01730250111016
UR  - https://pubmed.ncbi.nlm.nih.gov/4952156/
ID  - 4952156
ER  -