Reference to worksheet name using cell value

Hello to everyone, this is my first post on here. I have looked but couldn't find an answer to this.

I have worked as a programmer before so tended to do anything complicated using a program written for the purpose so have only used Excel occasionally. I have started to use it more often now and was trying to create a household budget planner.

I have created a seperate tab for each expense named for example 'mortgage', 'house insurance' etc.

On the first 'master' page I can refer to data on the other pages without problem but, rather than typing the name on a worksheet numerous times, is there a way of using the value of one cell as the name of the reference worksheet. ie

| 8 | 9 | 10
A | mortgage | =mortgage!$B$4 | =mortgage!$B$6


The column 8 has the name of the worksheet in it and I wanted to replace the word 'mortgage' in the reference of A9 and A10. This will make errors less likely and updating/adding etc easier.

Something like a9 being =(A8)!$B$4 <<<<-- This obviously doesn't work

Thanks in anticipation...