APA

Ricardo C., . (1990). Data base systems. New York: MaCmillan publishing company.

Chicago

Ricardo Catherine, . 1990. Data base systems. New York: MaCmillan publishing company.

Harvard

Ricardo C., . (1990). Data base systems. New York: MaCmillan publishing company.

MLA

Ricardo Catherine, . Data base systems. New York: MaCmillan publishing company. 1990.