Garudapurana 1.133.15

1.133.15

japtvā daśākṣarīṃ vidyāṃ nāsau kenāpi badhyate /
pañca (ñcā) daśāṅgulaṃ khaḍgaṃ triśūlaṃ ca tato yajet /
liṅgasyāṃ pūjayedvāpi pāduke 'tha jale 'pi vā //

Having recited the ten-syllabled spell, he is not bound by anyone. / Then one should worship a sword measuring fifteen aṅgulas and a trident; / or one may worship her residing in a liṅga, in sandals, or even in water.