Unless real estate brokers had the exclusive right to make a sale of certain property, they were not entitled to a commission if the sale was made by some one else, even though they secured a purchaser. Rothenberger v. Turner, 30 Ky. L. R. 1018, 99 S. W. 1150; Hennings v. Persons, 108 Va, 1, 61 S. E. 866; Mueller v. Bell (Tex. Civ. App. '09), 117 S. W. 993.