Abstract bulletin of the Institute of Paper Chemistry -1991
Bibliography of agriculture -1991
BioBusiness -1990
Biological abstracts -1990
Canadian Environment -1991
Chemical abstracts 1989-1991
Energy research abstracts -1991
Engineering index annual (1968) -1991
GeoRef -1991
International aerospace abstracts -1991
Physics abstracts -1991
Selected water resources abstracts -1991