¹ http://roarmap.eprints.org/ .

² http://core.ac.uk/intro/api .

³ http://core.ac.uk/intro/data_dumps .

⁴ http://core.ac.uk/ .

⁵ http://core.ac.uk/intro/plugin .

⁶ http://core.ac.uk/intro/dashboard .

⁷ https://scholar.google.co.uk/ .

⁸ http://citeseerx.ist.psu.edu .

⁹ https://www.openaire.eu/ .

¹⁰ https://www.ncbi.nlm.nih.gov/pubmed .

¹¹ https://www.openarchives.org/OAI/openarchivesprotocol.html .

¹² https://www.openarchives.org/pmh/tools/tools.php . P>

¹³ http://dublincore.org/ .

¹⁴ http://www.crossref.org/ .

¹⁵ Read more at point 3 http://blog.core.ac.uk/2015/10/19/7-tips-for-successful-harvesting/.

¹⁶ Read more at point 5 http://blog.core.ac.uk/2015/10/19/7-tips-for-successful-harvesting/.

¹⁷ http://www.irus.mimas.ac.uk/ .

¹⁸ http://rioxx.net/ .

¹⁹ http://www.rcuk.ac.uk/research/openaccess/policy/ .

²⁰ http://rioxx.net/guidelines/RIOXX_Metadata_Guidelines_v_3.0.pdf .