APA

Willems N., Easley J. T. & Rolfe S. T. (19). Strenght of Materials. New York: McGraw - Hill.

Chicago

Willems Nicholas, Easley John T and Rolfe Stanley T. 19. Strenght of Materials. New York: McGraw - Hill.

Harvard

Willems N., Easley J. T. and Rolfe S. T. (19). Strenght of Materials. New York: McGraw - Hill.

MLA

Willems Nicholas, Easley John T and Rolfe Stanley T. Strenght of Materials. New York: McGraw - Hill. 19.