The legislator defines copyright in Article 1 of the Dutch Copyright Act as follows:
'The exclusive right of a creator of a literary, scientific or artistic work, or of his assignees, to publish or reproduce it, subject to the limitations imposed by law.'
Copyright is a right granted by law to the creator. As an author, it gives you rights over the work you have created. Copyright is an exclusive right. This means that, as the creator, you decide what happens to your work. You have the sole, exclusive right to exploit your work: this is also called exploitation right.
Copyright takes effect from the moment the work is created. You do not need to apply for or register anything for this. After the creator's death, copyright passes to the heirs. Throughout the European Union the duration of copyright continues until 70 years after the death of the creator. Then the work enters the public domain.
If you have created a unique work, you get copyright on it. You keep this right as long as you are alive.
After death, this right passes to the heirs. They keep this copyright until 70 years after the creator's death. The duration of copyright applies throughout the European Union.
After those 70 years, the work enters the public domain. When a work has become public domain, it means that the copyright has expired. Heirs can no longer claim it. The work can now be freely used and edited by anyone.
However: if the copyright has expired it does not mean that you no longer have to mention the resource. You must always mention that the new work is based on the work of the creator who has since passed away.
Difference European Union - America
In the European Union, the copyright term for heirs is 70 years after the death of the creator. In America, that term is 95 years.
If a work is published with a Creative Commons license, it means that you can use it under certain conditions.
These conditions are described in the type of license. The rights to the work remain with the creator.
You do not need to ask permission to use this material. Depending on which license the creator has chosen, you can even adapt the work to your needs. You often have to mention that you have done so.
There are six Creative Commons licences available from which the creator can choose. You can read about the differences here.
The website of auteursrechten.nl says: 
'Plagiarism is copying data from someone else's work without proper acknowledgement of the source and presenting it as your own work in that way. It is intellectual theft and is considered fraud. Plagiarism violates the basic principles of the ALLEA code; the European Code of Conduct for Scientific Integrity. Through paraphrasing, quoting and referencing, you can prevent plagiarism.'
You can prevent plagiarism by practicing source citation.
Reminder:
Copyright expires 70 years after the death of the creator (in the European Union. For America, 95 years applies).
Plagiarism never expires.
There are different reference styles that can be used to show which resources you have used to substantiate your assignment/research.
At Saxion, APA7 is the most commonly used reference style. Each type of resource should be mentioned according to a guideline. How to apply the APA7 guidelines can be read in De APA- richtlijnen uitgelegd (in Dutch).
There is also the library guide APA-guidelines (based on APA 7).