GSM BCCH frame format

I want to read the cell identity and location area identification from the BCCH frame transmitted by the BTS. I am not able to get the exact frame format over which the LAI and cell identity will be located.
Also the BCCH is transmitted over a specific frequency which can be any of the 34 frequencies decided by specific ARFCN numbers. Can anyone help me get this 34 ARFCN numbers over which BCCH may be transmitted