[Theme Horse Support Team]

Hi Elena,

The <pre> tag defines preformatted text.
Text in a <pre> element is displayed in a fixed-width, and it preserves both spaces and line breaks.

So you have to break the line in editor like below

<pre>
Acinas SG*, Ferrera I*, Sarmento H, Díez-Vives C, Forn I, 
Ruiz-González C, Cornejo-Castillo FM, Salazar G, Gasol JM. 2015. 
- Environmental Microbiology * Equal contributors.
</pre> 

Thank you!