Reference: #. Author Last name Initials. Title [medium type]. Host institution name: Physical location; Year of publication [Date accessed].Available from: Identifier
24. Institute for Social and Economic Research. Understanding Society: Wave 1, 2009-2010 [data file]. University of Essex: Colchester, Essex; 2011. [cited 29 May 2013]. Available from: DOI: http://dx.doi.org/10.5255/UKDA-SN-6614-2#sthash.FhHerloZ.dpuf
Use a superscript number (like this: ¹) in the text at the place where you are indicating that you are citing from a source.
The WAVE data showed that a key factor in whether a mother returned to worked was the age of her youngest child.24