This is a quote from the book "The ​Virtue Of Selfishness" by Ayn Rand
...rvices — from the right of all those involved to pro- duce and to sell their products — from the right of the customers to buy (or not to buy) those products. Every link of this complex chai n of contractual relationships rests on individual rights, individual choices, individual agreements. Every agreement is delimited, specified and subject to certain conditions, that is, dependen t upon a mutual trade to mutual benefit.

This is true of all legitimate groups or associations in a free society: partnerships, business concerns, professional associations, labor ...
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