- Author: Humayun Kabir
- Language: English
- Year: 1963
- Author: Frits Staal
- Language: English
- Year: 1961
- Author: K.K. Pillay
- Language: English
- Year: 1977
- Author: Gopāla Śaraṇa
- Language: English
- Year: 1972
- Author: Kallidaikurichi Aiyah Nilakanta Sastri Sastri K. A. Nilakanta
- Language: English
- Year: 1939
- Author: Chelnat Achyuta Menon, University of Madras
- Language: Malayalam
- Year: 1935
- Author: SIVARAJA PILLAI
- Language: English
- Year: 1932
- Author: Balachandran V.K.
- Language: English
- Year: 2007