TY - JOUR AU - Molnar, Lajos TI - Maps preserving general means of positive operators JO - The electronic journal of linear algebra PY - 2011 SP - 864 EP - 874 VL - 22 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/ELA_2011__22__a19/ LA - en ID - ELA_2011__22__a19 ER -