外測度
Federer, H. (1996). Geometric Measure Theory. Classics in Mathematics (1st ed reprint ed.). Berlin, Heidelberg, New York: Springer Verlag. ISBN 978-3540606567
Kolmogorov, A. N.; Fomin, S. V. (1970). Introductory Real Analysis. Richard A. Silverman transl.. New York: Dover Publications. ISBN 0-486-61226-0