Aṣṭāṅgahṛdayasaṃhitā

Sarvāṅgasundarā

dvividhaṃ-dviprakāraṃ ca tadupakramaṇaṃ ca dvividhopakramaṇam, tasmai hito dvividhopakramaṇīyaḥ| śeṣaṃ pūrvavat| upakramaśca samāsato dvividhaḥ, tantrāntarapaṭhitānāṃ caturṇāmupakramāṇāmatraivāntarbhavāt|