Key points are not available for this paper at this time.
Citation: Newton, P. N. et al. (2009). 'Guidelines for field surveys of the quality of medicines: a proposal', PLoS Medicine, 6(3), e1000052. Available at http://www.plosmedicine.org. This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration, which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise by anyone for any lawful purpose.
Newton et al. (2009) studied this question.