TY  - JOUR
AU  - Kenneth Schilling
TI  - On absolutely $Δ^1_2$ operations
JO  - Fundamenta Mathematicae
PY  - 1984
SP  - 239
EP  - 250
VL  - 121
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.4064/fm-121-3-239-250/
DO  - 10.4064/fm-121-3-239-250
LA  - en
ID  - 10_4064_fm_121_3_239_250
ER  -