Citazione Stile APA (7a Edizione)

Helmers, F. L. C. H. (1979). Project planning and income distribution. M. Nijhoff.

Citazione stile Chigago Style (17a edizione)

Helmers, F. Leslie C. H. Project Planning and Income Distribution. Boston: M. Nijhoff, 1979.

Citatione MLA (9a ed.)

Helmers, F. Leslie C. H. Project Planning and Income Distribution. M. Nijhoff, 1979.