This is the function I currently have:
=IF(L2<"",INDIRECT("'"&L2&"'!B"&ROW($A$2)),"")

I want to modify it in the following way....
=IF(L2<"", {IF STATEMENT} INDIRECT("'"&L2&"'!B"&ROW($A$2)),"")

I want to add another if statement where shown above to check if there is a
sheet called '"&L2&'"! . So basically IF('"&L2&'"! EXISTS, TRUE, FALSE)

Thanks in advance for any help!