(1957). Rubber Vithukal Mulappikkunna Reethi. Kottayam: Rubber Research Institute of India.
1957. Rubber Vithukal Mulappikkunna Reethi. Kottayam: Rubber Research Institute of India.
Rubber Vithukal Mulappikkunna Reethi. Kottayam: Rubber Research Institute of India. 1957.
