Williams, K. W. (1970). Arithmetic: A semiprogrammed text. Prentice-Hall.
芝加哥风格引文Williams, Keith W. Arithmetic: A Semiprogrammed Text. Englewood Cliffs, N.J.: Prentice-Hall, 1970.
MLA引文Williams, Keith W. Arithmetic: A Semiprogrammed Text. Prentice-Hall, 1970.
警告：这些引文格式不一定是100％准确.