springhead
mother
ur-source
straight from the horse's mouth
root
emanate
from good hands
at first hand
firsthand
give birth
trufax
reference
authorship
have something on good authority
title
underpinning
last word
founded
oroclinal
outpart
factually
magisterium
fons et origo
scripture
forenote
factualist
wartweed
uredinous
uredineous
intersource
prediscovery
guest
afore-explained
uredosporous
by
factically
uredosporic
relevantly
grass roots
issuing
rise
straight
font
foundation stone
acceptable
meat and potatoes
clue
foretalk
matter of fact
beforestated