Crossmark policy

Crossmark is an initiative to provide a standard way for readers to locate the current version of a piece of content. By applying the Crossmark button, Letters on Materials is committing to maintaining the content it publishes, and to alerting readers to changes if and when they occur. Clicking on the Crossmark button will tell you the current status of a document, and may also give you additional publication record information about the document.

Minor correction
The minor correction is an unsubstantial correction that can be related to spelling or formatting. When a minor correction is required in a published article, the Editors perform in-situ correction of the article without publishing Correction Notice. The original PDF file is replaced with updated one.

Major correction

When a significant mistake is found (by readers, authors or editors) in a published article, and the mistake does not affect integrity and conclusions of the article, the Editors publish a Correction Notice. For example, the mistake can be in the reported data or units. The Correction Notice clearly states the title and DOI of the original article. Also, the Correction Notice clearly reports the full list of amendmends, provided by authors, to correct the mistake. The Correction Notice receives individual DOI that is differernt from the DOI of original paper.

Retraction
If any rule of the Publication Ethics is violated, Retraction of an article can be initiated by Editors after investigation. To inform readers about retraction, the Editors perform the following actions:

1) On the webpage with original article, the Editors make it clear that the article is retracted by a) reflecting the retraction in the title of the article, b) replacing the original Abstract with retraction reasons, c) adding "retracted" watermark in the original PDF file.

2) A Retraction Notice is published by Editors in the soonest volume. The Retraction Notice clearly states title and DOI of original paper. Also, the reasons for retraction are provided. The Retraction Notice receives individual DOI that is different from the DOI of the original paper.