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