From: Zeekoefontein
This Prisoner of War record for Jan Jacob Roestorf was transcribed record from various documents held at the National Archives, South Africa, including arrest and shipping information from newspaper sources like De Zuid-Afrikaan.
https://www.gendatabase.com/boer-war-prisoner-record.php?q=18305&r=Jan Jacob&s=Roestorf&ref=
This set of Prisoner of War documents can be accessed online via the FamilySearch.org project by Clicking Here.