Assuming I have
Sheet1!A1 with value 100
Sheet2!B1 with "Sheet1" without cotes - the Sheet1 name

In
Sheet2!B2 I want the same value of Sheet1!A1

Firs way
=Sheet1!A1 and the result is 100

But I want to refer Sheet1, in that formula, by its name typed in Sheet2!B1
Then I tried fill in Sheet2!B2 this
=Indirect(B1)!A1 but it gives error.

HOW CAN I REFER SHEETS BY ITS NAMES TYPED IN ONE PARTICULAR SHEET??

GRATIAS FOR HELP