1. FROM THE BOOK INDIAN CASTE BY JOHN WILSON
http://books.google.com/books?id=uTTB8Px-jt4C&pg=RA1-PA87&lpg=RA1-PA87&dq=cholas+caste&source=web&ots=UvbreRc6lS&sig=A4r9KGDOqkaAPIg9t9Eo34ljO44#PRA1-PA87,M1
2. Castes and Tribes of Southern India (1909), Vol. III;
http://72.14.235.104/search?q=cache:6WonBjpWbMwJ:www.hinduonnet.com/fline/fl2016/stories/20030815004703800.htm+cholas+caste&hl=en&ct=clnk&cd=95&gl=in
The district itself was earlier part of a larger Madura district. Edgar Thurston, the renowned museologist and ethnographer, states in his Castes and Tribes of Southern India (1909), Vol. III; in the entry on Kallan: "Portions of the Madura and Tanjore districts are divided into areas known as nadus, a name which, as observed by Mr. Nelson, is specially applicable to Kallan tracts." (page 72) (Kallan or Kallar denotes a caste group, which is part of the Mukkulathor, now a dominant caste in the southern districts of Tamil Nadu. Maravar and Agamudaiyar are the other components of the Mukkulathor community. The Chola country of Tanjore is stated to be the original abode of the Kallars before they migrated to the Madurai region, the then Pandya kingdom. Agriculture was said to be their major occupation.) On the whole there were 37 "nadus" in the two districts, of which 14 were said to be in the Sivaganga region. ("Nadu" was a group of villages under the Chola administrative system.)
3. http://www.sangam.org/articles/view2/?uid=1072
