APA

Helmers G., Rumar K., . (1973). Obstacle visibility in rural night driving as related to reflective qualities of the road surface. Uppsala: Uppsala universitet. Department of psychology. Report nr 137.

Chicago

Helmers G, Rumar K, . 1973. Obstacle visibility in rural night driving as related to reflective qualities of the road surface. Uppsala: Uppsala universitet. Department of psychology. Report nr 137.

Harvard

Helmers G., Rumar K., . (1973). Obstacle visibility in rural night driving as related to reflective qualities of the road surface. Uppsala: Uppsala universitet. Department of psychology. Report nr 137.

MLA

Helmers G, Rumar K, . Obstacle visibility in rural night driving as related to reflective qualities of the road surface. Uppsala: Uppsala universitet. Department of psychology. Report nr 137. 1973.