APA

Crawford C., . (1955). Frost penetration studies in Canada as an aid to construction. ( Roads and Engineering Construction. Vol 93. 1955. Nr 2, Feb). Ottawa: National Research Council Canada. Technical paper nr 20.

Chicago

Crawford CB, . 1955. Frost penetration studies in Canada as an aid to construction. ( Roads and Engineering Construction. Vol 93. 1955. Nr 2, Feb). Ottawa: National Research Council Canada. Technical paper nr 20.

Harvard

Crawford C., . (1955). Frost penetration studies in Canada as an aid to construction. ( Roads and Engineering Construction. Vol 93. 1955. Nr 2, Feb). Ottawa: National Research Council Canada. Technical paper nr 20.

MLA

Crawford CB, . Frost penetration studies in Canada as an aid to construction. ( Roads and Engineering Construction. Vol 93. 1955. Nr 2, Feb). Ottawa: National Research Council Canada. Technical paper nr 20. 1955.