TY  - JOUR
AU  - Apostolakis, Nikos
TI  - On 4–fold covering moves
JO  - Algebraic and Geometric Topology
PY  - 2003
SP  - 117
EP  - 145
VL  - 3
IS  - 1
UR  - http://geodesic.mathdoc.fr/articles/10.2140/agt.2003.3.117/
DO  - 10.2140/agt.2003.3.117
ID  - 10_2140_agt_2003_3_117
ER  -