array(3) {
  [0]=>
  int(15821)
  [1]=>
  string(158) "Bhowmik R., Wang S. Stock market volatility and return analysis: A systematic literature review // Entropy. 2020. vol. 22(5). no. 522. DOI: 10.3390/e22050522."
  [2]=>
  int(1)
}
<h1>DB Error 230: Duplicate entry '15821-1' for key 'citations.citations_submission_seq'</h1>