Shrestha, M., Kukkonen-Harjula, K.T., Verbeek, J.H., Ijaz, S., Hermans, V. and Pedisic, Z. (2018) ‘Workplace interventions for reducing sitting at work’, Cochrane Database of Systematic Reviews, 12, CD010912. doi: 10.1002/14651858.CD010912.pub5.
As this example has more than 3 authors, you would use Shrestha et al. 2018 in your citation in your text.
This example of referencing applies specifically to Cochrane Systematic Reviews. The Clinical Trials section consists of journal references so you should reference this information using the journals format.
NICE (2021) Safeguarding adults in care homes. NG189. Available at: http://www.nice.org.uk/guidance/ng189 (Accessed: 01 March 2021).
If the organisation is well known then you may use their intials, as long as you are sure that the person reading your assignment will recognise them (e.g. you may wish to use SGUL in place of St. Georges, University of London). NICE is also likely to be commonly known, but if in doubt, check with your tutor or module leader.
You can apply this method for guidelines and protocols from other health, government, professional and corporate bodies. If they do not have a designated number, you just use the title of the guideline/protocol.