A.A.U. One-Wall Rules · American one-wall, small ball
Rule 4
HistoricalA.A.U. One-Wall Rules, 20 November 1922 (historical)
First service shall be determined by the toss of a coin, or in any other manner agreed by the contestants.
Mentioned here
How this rule changed
See the wording of this rule in every rulebook, with the changes marked.