Before revision: <ref> The technical definitions of this section rely heavily on cite book|first=Pierre Y.|last=Julien|title=River Mechaniure varies from a maximum at the apex to zero at a crossing point (straight line), also called an inflection, because the curvature changes direction in that vicinity.
After revision: The technical definitions of this section rely heavily on varies from a maximum at the apex to zero at a crossing point (straight line), also called an inflection, because the curvature changes direction in that vicinity.