APA
Popper K. R., . (1968). Conjectures and refutations : the growth of scientific knowledge. New York ; Evanston: Harper & Row Publishers.
Chicago
Popper Karl R, . 1968. Conjectures and refutations : the growth of scientific knowledge. New York ; Evanston: Harper & Row Publishers.
Harvard
Popper K. R., . (1968). Conjectures and refutations : the growth of scientific knowledge. New York ; Evanston: Harper & Row Publishers.
MLA
Popper Karl R, . Conjectures and refutations : the growth of scientific knowledge. New York ; Evanston: Harper & Row Publishers. 1968.