ŚBM, 6, 7, 1, 28.2 catvāraḥ pādāś catvāry anūcyāni śikyaṃ ca rukmapāśaśca yad u kiṃ ca rajjavyaṃ śikyaṃ tad anūkhāgnī rukmas tat trayodaśa trayodaśa māsāḥ saṃvatsaraḥ saṃvatsaro 'gnir yāvān agnir yāvatyasya mātrā tāvat tad bhavati //