Barus, W. A., H. Khair, and M. F. Irawan. “Growth Response and Production of Broccoli (Brassica Oleracea) With Application of Azolla Composting at Several Plant Spacing”. Indonesian Journal of Agricultural Research, vol. 1, no. 2, Sept. 2018, pp. 179-86, doi:10.32734/injar.v1i2.177.