When it appears from the estimates of cost that the estimated contract price of any project will not exceed fifteen thousand dollars ($15,000), the trustees may direct that public notice to bidders be given as follows:
(a)
By publication for two consecutive insertions in a weekly trade paper of general circulation, published either in Los Angeles or San Francisco, devoted primarily to the dissemination of contract news among contracting firms; and
(b)
Once a week for two consecutive weeks in a newspaper of general circulation in the county in which the project is located, or, if located in more than one county in such a newspaper in a county in which a major portion of the work is to be done.