Śaiśirīya Śikṣā 75

75

kramakāle rathānānna saṃhitāvanna kaṃpayet
nīcasvaritamevātra eṣa kampavidhiḥ smṛtaḥ

At the time of step recitation of "rathānām", one should not shake as in continuous recitation; / only the grave-circumflex is here: this is remembered as the rule of kampa.