Columbia subject headings:
Harvard subject headings:
Agricultural engineers--Switzerland--Biography.
Agricultural pests--Biological control
Herren, Hans Rudolf, 1947-
Insect pests--Biological control
Sustainable agriculture
Princeton subject headings:
Agricultural engineers--Switzerland--Biography.
Agricultural pests--Biological control.
Herren, Hans Rudolf, 1947-
Insect pests--Biological control.
Sustainable agriculture.