APA

Dalberg Poulsen A., Haubjerg Nielsen I., .How many ferns are there in one hectare of tropical rain forest?. : .

Chicago

Dalberg Poulsen Axel, Haubjerg Nielsen Ingvar, .How many ferns are there in one hectare of tropical rain forest?. : .

Harvard

Dalberg Poulsen A., Haubjerg Nielsen I., .How many ferns are there in one hectare of tropical rain forest?. : .

MLA

Dalberg Poulsen Axel, Haubjerg Nielsen Ingvar, .: . .