Duplicate submission or publication refers to the practice of submitting the same manuscript to two journals or publishing more or less the same content in two journals. These submissions/publications can be nearly simultaneous or years later.
Redundant publication refers to the situation that one study is split into several parts and submitted to two or more journals. Or the findings have previously been published elsewhere without proper cross-referencing, permission or justification. Self-plagiarism is also considered as a form of redundant publication. It concerns recycling or borrowing content from previous work without citation. This practice is widespread and might be unintentional. Transparency by the author on the use of previously published work usually provides the necessary information to make an assessment on whether it is deliberate or unintentional.
Science Text Publishers will strictly follow the guidelines and won’t allow such practices.