[1] HUNGARIAN ACAD SCI, HUNGARIAN NAT HIST MUSEUM BALATON LIMNOL INST, DEPT BOT, H-8237 TIHANY, HUNGARY
[2] NERC, FRESHWATER BIOL ASSOCIAT, INST FRESHWATER ECOL, WINDERMERE LAB, AMBLESIDE LA22 0LP, ENGLAND
[3] EOTVOS LORAND UNIV, DEPT PLANT TOXON & ECOL, H-1083 BUDAPEST, HUNGARY