Does a sister on my mother's side have the right of inheritance? If so, how much is her share? Also, I am married and have two boys and two girls, a full brother and sisters on my father's side and a mother. After my death how will the inheritance be divided? Is there a book about inheritance that I can use?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

If male or female children or grandchildren of a deceased are alive, or his father or grandfather still exist, then the half-brothers and sisters from the mother's side do not inherit.  Allah Says (interpretation of meaning): {…If the man or woman whose inheritance is in question has left neither ascendants nor descendants, but has left a brother or a sister, each one of the two gets a sixth; but if more than two, they share in a third;…..}[4:12].

If there is only one brother or sister from mother’s side he/she will take one sixth of the inheritance. If there are more than one, they will share in the "one-third" of the inheritance. The female takes the same share as that of the male.

If a man dies and leaves two sons, two daughters, a full brother, and full or half sisters and a wife, the wife takes an eighth of all the inheritance, Allah Says (interpretation of meaning): {…but if you leave a child, they (the wives) get an eighth of that…..}[4:12]. The remaining inheritance is distributed among the male and female children of the deceased; the share of a female is half the share of a male. 

Allah knows best.