Create hyper-link to child records within a formula text field?

Normally you can click on a hyper-link of a numeric summary field to drill down and see the related child records.  When I incorporate the value of the summary field into a formula text field, the hyper-link disappears so I can't drill down.  What are ALL the methods to link to the desired child records in a formula text field?? 

I've used the <a href> html tag linked to an <ask-the-user> report with multiple criteria. This works, but I am wondering if there are any other methods? 

Thanks