APA

Erlander S., . (1982). Gravity model in transportation planning derived as an approximate aggregate utility model. Linköping: Linköpings Universitet. Matematiska Institutionen. Rapport 82-12.

Chicago

Erlander S, . 1982. Gravity model in transportation planning derived as an approximate aggregate utility model. Linköping: Linköpings Universitet. Matematiska Institutionen. Rapport 82-12.

Harvard

Erlander S., . (1982). Gravity model in transportation planning derived as an approximate aggregate utility model. Linköping: Linköpings Universitet. Matematiska Institutionen. Rapport 82-12.

MLA

Erlander S, . Gravity model in transportation planning derived as an approximate aggregate utility model. Linköping: Linköpings Universitet. Matematiska Institutionen. Rapport 82-12. 1982.