APA
Edwin G. Valencia, Gregorio F. Roxas, . (2001). Income taxation: principles and laws with accounting applications. Baguio City: Valencia Educational Supply.
Chicago
Edwin G. Valencia, Gregorio F. Roxas, . 2001. Income taxation: principles and laws with accounting applications. Baguio City: Valencia Educational Supply.
Harvard
Edwin G. Valencia, Gregorio F. Roxas, . (2001). Income taxation: principles and laws with accounting applications. Baguio City: Valencia Educational Supply.
MLA
Edwin G. Valencia, Gregorio F. Roxas, . Income taxation: principles and laws with accounting applications. Baguio City: Valencia Educational Supply. 2001.