APA

Pork A., . (1986). Some aspcects of relative causal importance in history. Tallinn: Academy of sciences of The Estonion SSR.

Chicago

Pork A, . 1986. Some aspcects of relative causal importance in history. Tallinn: Academy of sciences of The Estonion SSR.

Harvard

Pork A., . (1986). Some aspcects of relative causal importance in history. Tallinn: Academy of sciences of The Estonion SSR.

MLA

Pork A, . Some aspcects of relative causal importance in history. Tallinn: Academy of sciences of The Estonion SSR. 1986.