Plagiarism is using someone else's written work, ideas or creations without acknowledgment, even if is re-written in your own words. Plagiarism can be a serious academic and legal offense, even if it was done by mistake. You can avoid plagiarism by carefully citing all resources that were used to write your paper. Things that can be considered general knowledge, such as "the sky is blue," do not need to be cited. If you are unsure whether something is general knowledge, it is always best to cite a reference even if you did not use one; with the internet at your fingertips, it is easy to find the person who originally came up with the thought, idea or knowledge and cite the reference. Always err on the side of caution.
Research papers are oftentimes helpful documents for readers, especially when they include citations that provide direction to other related sources for further reading. If a reader can backtrack the research that you have done to write your paper, they can get a better understanding of the subject matter and gain knowledge in that area. Although this may seem like a courtesy, it is essential for professional papers so that the reader can understand how you came to the conclusions suggested in your research paper.
Because the sources that you used to write the research paper were obviously helpful, you should always cite the original authors to give credit for their professional work. In the professional and academic world, being cited can be seen as prestigious and can lead to business opportunities for professionals. If someone else's work was used to assist in your paper, it is only fair that the person gets credit for the help. It is not only a legal requirement, but it is an unspoken rule of courtesy among students and professionals. Just remember, if someone ever used your work to write a research paper, it would be important to you to get recognition for your contribution. Everyone deserves recognition for a job well done.
The more references you provide, the more credible your research paper will be. You will be perceived as a competent and well-written author if the your paper is founded on a variety of knowledge and previous research. For students, this is important to be seen as a capable writer and researcher to earn a good grade; for professionals, this is important to give your work an edge and gain respect, credentials and to succeed in your career.