The soliciting of alms and contributions, commercial soliciting and vending of all kinds, the display or distribution of commercial advertising, or the collecting of private debts, in or on Research Center property, is prohibited. This section does not apply to national or local drives for funds for welfare, health, and other purposes sponsored or approved by the Agricultural Research Service, concessions, or personal notices posted by employees on authorized bulletin boards. Distribution of material such as pamphlets, handbills, and flyers or the posting of mateirals on bulletin boards or elsewhere, is prohibited without prior approval of authorized individuals.