It is important that you specify who your competition is, and up to what extent you want the authors to use the information on their websites. You can ask them to document themselves using them or not. To do this, you need to tell them who they are and if you want them to reflect their names in the content or not.
Note that all these specifications can only be made in the Advanced Briefing, and in the request to purchase content through the Excel sheet.
Please consider that if in ‘Format Requirements’ you indicate that they use hyperlinks to reference sources, there may be a contradiction. You can suggest them not to use hyperlinks to the competition, but to other sources instead (for example, to official sources, specific brands, expert blogs, influencers, etc.)