* cumulative aggregations

* Apply suggestions from code review

Co-authored-by: Jeff Bruemmer <jeff.bruemmer@gmail.com>

* cumulative articles

* consolidate cumsum and cumcount articlesa

* links

* remove previews

* sort clarification

* Apply suggestions from code review

Co-authored-by: Jeff Bruemmer <jeff.bruemmer@gmail.com>

* link

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Co-authored-by: Jeff Bruemmer <jeff.bruemmer@gmail.com>