1.GERMANY
•INSTITUTE FOR
FLOODPLAINS ECOLOGY – WWF RASTATT 1990
2.
The NETHERLANDS
•INSTITUTE FOR INLAND
WATER MANAGEMENT AND WASTE WATER TREATMENT – RIZA – LELYSTAD 1992
3.FRANCE
•STATION BIOLOGIQUE TOUR DU VALAT – CAMARGUE 1996
4.GREAT BRITAIN
•NATURAL RESOURCES INSTITUTE – NRI – UNIVERSITY OF
GREENWICH 1999