TY  - JOUR
AU  - Christian Berg
AU  - Zoltán Sasvári
TI  - Functions with a Finite Number of Negative Squares on Semigroups.
JO  - Monatshefte für Mathematik
PY  - 1989
SP  - 9
EP  - 34
VL  - 107
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MOMA_1989__107_3_178410/
ID  - MOMA_1989__107_3_178410
ER  -