array(3) {
  [0]=>
  int(4374)
  [1]=>
  string(226) "Wan J., Tang S., Shu Z., Li D., Wang S., Imran M., Vasilakos A. V. Software-defined industrial internet of things in the context of industry 4.0. IEEE Sensors Journal, 2016, no 20, pp. 7373-7380. doi:10.1109/ JSEN.2016.2565621"
  [2]=>
  int(1)
}
<h1>DB Error 230: Duplicate entry '4374-1' for key 'citations.citations_submission_seq'</h1>