book name "Basic ESD and I/O Design"
author Dr Sanjay Dabral; Dr Timothy J. Maloney
Since IO cell layout development is largely influenced by the ESD issues, this is the right book
Furthur
Any I/O layout called corel limited onlyf if io layout dimention have less hight and more width
this gives more core area
in case of pad limited IO , more IOs can be placed in IO ring. So stress on less width and more hight, so number of IO that can be placed in the IO ring limited by bond pad placement.