Please find the book written by Jordan Oliver, former Yale football
coach, on the T-formation Belly Series. Especially, where can copies
of the book be purchased?

I've found references to the book, but have not found it available for
purchase. Note that the last name is spelled "Olivar."

"Olivar, Jordan - Offensive Football: The Belly Series - Ronald Press, 1958"

http://www.footballbooklist.com/list.html

can't find a place to buy the book. 
If you would like to know a library near you, to get hold of the book,
please provide your postal code.

It is available here. http://www.lib.udel.edu/ud/spec/findaids/nelson4.htm
But it might be available some place close to you.

I am having a hard time finding a place to find the book.

However, I did find out that they have since re-released the book
(2003).  You can find most of the information you need to find the
availability of the book at:

http://www.bookfinder.com/search/?ac=sl&st=sl&qi=U6CLYQvfTUcj6Biwt5VD9S6rySo_4210534989_2:5:6


You can find the date published and similar information at:

http://www.campusi.com/bookFind/asp/bookFindPriceLst.asp?prodId=0758147279


It also appears to be located at the Harvard-Yale Football Gallery;
http://www.the-game.org/books/books-offensivefootball.htm

Hope this helps.