APA

Summala H., Rämä A., .Expectancy and obstacle avoidance by the blind. Helsingfors: Helsinki University. Psychology.

Chicago

Summala H, Rämä A, .Expectancy and obstacle avoidance by the blind. Helsingfors: Helsinki University. Psychology.

Harvard

Summala H., Rämä A., .Expectancy and obstacle avoidance by the blind. Helsingfors: Helsinki University. Psychology.

MLA

Summala H, Rämä A, .Helsingfors: Helsinki University. Psychology. .