Copyright Act Article 36

Economic rights may be transferred in whole or in part to another person and may be jointly owned with other persons.The transferee of economic rights obtains economic rights within the scope of the transfer.The scope of the transfer of the economic rights shall be as stipulated by the parties; rights not clearly covered by such stipulations shall be presumed to have not been transferred.
中文原文 著作權法第36條
著作財產權得全部或部分讓與他人或與他人共有。
著作財產權之受讓人,在其受讓範圍內,取得著作財產權。
著作財產權讓與之範圍依當事人之約定;其約定不明之部分,推定為未讓與。

English translation for reference only; the Chinese text prevails. Not legal advice.