Section 17.3 Reference Topics
This site gives a nice overview of apportionment methods.
http://www.ctl.ua.edu/math103/apportionment/appmeth.htm#Apportionment
You can find the reference to Article 1, Section 2 of the United
States Constitution (amoung many other interesting things) at this site:
http://www.law.cornell.edu/constitution/constitution.articlei.html
This excellent site from the Census Bureau does a nice historical
overview of apportionment in the House of Representatives.
http://www.ctl.ua.edu/math103/apportionment/apphisty.htm
Data from the first federal congress can be found here:
http://www.gwu.edu/~ffcp/exhibit/p14/