APA

International Congress on Soilless Culture, . (1977). Proceedings of the fourth International Congress on soilless culture. Wageningen: International Working Group on Soilless Culture.

Chicago

International Congress on Soilless Culture, . 1977. Proceedings of the fourth International Congress on soilless culture. Wageningen: International Working Group on Soilless Culture.

Harvard

International Congress on Soilless Culture, . (1977). Proceedings of the fourth International Congress on soilless culture. Wageningen: International Working Group on Soilless Culture.

MLA

International Congress on Soilless Culture, . Proceedings of the fourth International Congress on soilless culture. Wageningen: International Working Group on Soilless Culture. 1977.