When you create a work, the Moral Rights of Authors and Copyright (Property Rights) is granted automatically, and it's protected under the Copyright Act. Therefore, when using another person's work as part of educational materials, in principle you must obtain authorization; however, there are Exceptional Rules (See Q4、Q5、Q8） which allow us to use copyrighted work without authorization. Also, if part of the Copyright (Property Rights) for papers which you wrote and published is transferred to an academic association or publishing company, unless it falls under these exceptional rules, you must obtain authorization from the transferee.