displaying values from a number of worksheets

I have a text in sheet2!A1, sheet3!A1,...sheet20!A1 and I want to display those values in sheet1!B1:B20. To automate the work, I put the text 'sheet1' in A1, 'sheet2' in A2....'sheet20' in A20.
What formula should be put in B1 and copy down to display the values from those worksheets?
Can I use INDIRECT()?
Thanks for your help

Re: displaying values from a number of worksheets

Displaying values from different worksheets

Further to previous post.
I have 6 values in sheet2, 2 values in sheet3, 10 values in sheet4. To display those values in sheet1, I can copy those values manually but I want to automate this work. What formula should be put in sheet1?
The problem is:
the numbers of values maybe different in different worksheets, how to put them in a single column in sheet1?
I have attached the xls for your ref. I want a formula in sheet1!A5 and copy down.
Thanks for your help