TY  - JOUR
T1  - What we now know about 'I don't knows'
AU  - Francis, Joe D.
AU  - Busch, Lawrence
PY  - 1975
DO  - 10.1086/268217
SP  - 207
EP  - 218
JO  - Public Opinion Quarterly
VL  - 39
IS  - 2
SN  - 0033-362X
ER  -