Where the power is conferred by a mandate in a written form, the power of attorney shall clearly state the agent's name and the object of, power conferred by, and term of the mandate, to which the signature or seal of the principal shall be affixed. 委托代理授权采用书面形式的，授权委托书应当载明代理⼈的姓名或者名称、代理事项、权限和期限，并由被代理人签名或者盖章。 Where the object of a mandate is to be performed by several agents, they shall jointly exercise the power conferred, except as otherwise agreed upon by the parties. 数人为同⼀代理事项的代理人的，应当共同⾏使代理权，但是当事人另有约定的除外。 Where an agent knows or should have known that the object of the mandate is illegal but still performs it, or the principal knows or should have known that an agent's performance is illegal but fails to raise any objection, the principal and the agent shall be jointly and severally liable. 代理人知道或者应当知道代理事项违法仍然实施代理行为，或者被代理人知道或者应当知道代理人的代理行为违法未作反对表示的，被代理理人和代理人应当承担连带责任。