Cita APA (7th ed.)
Helmers, F. L. C. H. (1979). Project planning and income distribution. M. Nijhoff Pub..
Cita Chicago (17th ed.)
Helmers, F. L. C. H. Project Planning and Income Distribution. Boston: M. Nijhoff Pub., 1979.
Cita MLA (9th ed.)
Helmers, F. L. C. H. Project Planning and Income Distribution. M. Nijhoff Pub., 1979.
Atenció: Aquestes cites poden no estar 100% correctes.