Manasara 18.42

18.42

dvātriṃśadvibhāgaṃ caiva trayastriṃśadvibhāgikam
madhyamaṃ dvādaśabhūmiṃ bhāgamānaṃ viśālake

and thirty-two parts, or thirty-three parts: / [such is] the proportional width for the intermediate twelve-storeyed [vimāna].