Q: How do I contact the author of an article published in a journal?

You have not mentioned which journal the article is published in. Published articles always have the names and affiliations of all the authors in the authors list. You can look for information about the author online using these details, and will probably come up with the author's website or the institutional website where the contact information is generally mentioned. The other option is to contact the editor of the journal where the article was published and request them to provide you the contact details of the author. Since you have a valid reason, they will surely give you the information.

Since you are interested in replication studies, you might find these resources helpful:

• Control, treat, repeat: Replicating an experiment on uncertainty
• Publishing a replication study