How to combine PDF files

From Adobe Acrobat to free online editors and built-in tools, here’s how to merge multiple PDFs into one document.
RMD Open

Patients with systemic lupus erythematosus (SLE) have an increased bisphenol A methylation score linked to SLE risk genes and selected clinical subphenotypes

Objectives Bisphenol A (BPA), a xenoestrogen that can alter DNA methylation status, has been implicated in the pathogenesis ...