APA
                    Johnsonbaugh R., . (2014). Discrete mathematics.-7th ed. Noida: Pearson.
                
                    Chicago
                    Johnsonbaugh Richard, . 2014. Discrete mathematics.-7th ed. Noida: Pearson.
                
                    Harvard
                    Johnsonbaugh R., . (2014). Discrete mathematics.-7th ed. Noida: Pearson.
                
                    MLA
                    Johnsonbaugh Richard, . Discrete mathematics.-7th ed. Noida: Pearson. 2014.