Cita APA (7a ed.)

Helmich, H. (1990). Directory of non - governmental development organizations in OECD member countries. OCDE.

Cita Chicago Style (17a ed.)

Helmich, Henry. Directory of Non - Governmental Development Organizations in OECD Member Countries. París: OCDE, 1990.

Cita MLA (9a ed.)

Helmich, Henry. Directory of Non - Governmental Development Organizations in OECD Member Countries. OCDE, 1990.