nonprobability sampling - Math bibliographies - in Harvard style

In-text: (Laerd dissertation, 2012)

Your Bibliography: 2012. Laerd dissertation. Non-probability sampling [Online] Available: (www.dissertation.laerd.com) [20 February 2015].

In-text: (Non-Probability Sampling, 2009)

Your Bibliography: Explorable.com. 2009. Non-Probability Sampling. [online] Available at: <http://explorable.com/non-probability-sampling> [Accessed 20 February 2015].

In-text: (Non-probability sampling, 2012)

Your Bibliography: Laerd dissertation. 2012. Non-probability sampling. [online] Available at: <http://dissertation.laerd.com/non-probability-sampling.php> [Accessed 20 February 2015].

In-text: (Smith, 2009)

Your Bibliography: Smith, K., 2009. Maths handbook and study guide. [Birnam Park]: Berlut Books, pp.227-228.

In-text: (Trochim, 2006)

Your Bibliography: Trochim, W., 2006. Nonprobability sampling. [online] Research Methods Knowledge Base. Available at: <http://socialresearchmethods.net/kb/sampnon.php> [Accessed 20 February 2015].

In-text: (Multistage sampling, 2014)

Your Bibliography: Wikipedia. 2014. Multistage sampling. [online] Available at: <http://en.wikipedia.org/wiki/multistage_sampling> [Accessed 20 February 2015].