Gaya APA

Ostrowski, R., Kemper, J. (1977). Echoes Of Time : A World History (Ed. 1). United State of America: Mcgraw-Hill Book Company, INC..

Gaya MLA

Ostrowski, Richard., Kemper, Jack. "Echoes Of Time : A World History". Ed. 1 United State of America: Mcgraw-Hill Book Company, INC., 1977. Text.