If authority of agency is conferred by a juridical act, it shall be made by an expression of intent to the agent or to the third party with whom the delegated act is transacted.

If there are several agents, the delegated act shall be transacted by them jointly, unless otherwise provided by the act or the principal's expression of intent.

A person, who by his own acts represents he has conferred the authority of agency to another person, or who knows that another person declares himself to be his agent and failed to express a contrary intent, shall be liable to the third party as a person who has conferred that authority, except the third party knew, or might know of the absence of authority.

A juridical act made in the name of an agent by a person of no authority of agency shall not be effective to the principal except it is acknowledged by the principal.
In the case specified in the preceding paragraph, the other party to the juridical act may fix a reasonable period and request the principal to declare definitely whether he acknowledges it or not. If the principal does not give a definite answer within the specified period, the acknowledgement shall be deemed to have been refused.

[The expression of intend in]A juridical act made by a person of no authority of agency may be withdrawn by the other party to the act before the acknowledgement of the principal, except where such other party knew of the absence of authority at the time of the act.