If, for example, you want to cite this article in your paper to support your argument, you should:
|.. Smart clothing technologies may include printed sensors able to monitor a wearer’s well-being or detect dangerous chemicals in the environment (Excell, 2013), ...|
|Excell, J. (2013, April 8). Smart dressing. Retrieved from https://www.theengineer.co.uk/content/in-depth/smart-dressing-advances-in-wearable-technology|
What about indirect sources?
For example, you read about Smith's idea (or research findings) in Nicholson's paper and you did not read Smith's article yourself. In this case, you CANNOT cite a source that you have not read, so you need to indicate that the information is obtained from a secondary source:
What about personal communications?
Personal communications may be private letters, memo, electronic communications (e.g. e-mail), personal interviews, telephone communications, etc. Because they are not considered recoverable data, so personal communications are not required in the reference list, but you have to cite personal communications within the text. Give the initials, follow by the surname (family name, last name, 姓) of the communicator, and provide the exact date as possible.
In-text Reference = (T.W. Lau, personal communication, September 2, 2012)
See A Guide to Good Referencing Skills for more tips on how to paraphrase and summarize sources.