In research writing, plagiarism is the most unethical and the most widely recognized ethical lapse. Critical and informative use and acknowledgement of other people’s work, where it is relevant to your work, is an essential and desirable part of any project and report. Plagiarism is the use, without adequate acknowledgement, of the intellectual work of another person. It is the most unethical writing practice.
Web materials are notoriously unreliable, may be inaccurate, only available for a short time, and there is generally no measure of accountability, therefore, avoid web references as much as possible.