Text and Data Mining valid from 2018-10-12
Received: 19 June 2018
Accepted: 19 September 2018
First Online: 12 October 2018
Change Date: 5 February 2019
Change Type: Correction
Change Details: Following publication of the original article , the author reported that the values for LV1, LV2, LV3 and LV4 in row “Website section” of Table 2 should be corrected as follows:
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