These are the references in support of "Telugu-Kannada script":
Dravidian Languages (see page 78,79 of this book)
TDIL telugu script
Indian Epigraphy..., by Richard Salomon
The Blackwell Encyclopedia of Writing Systems By Florian Coulmas
Indian Epigraphy, by Dineshchandra Sircar
  Transactions  By Archaeological Society of South India
IGNCA- Indian government institution