What is the pKaH of pyrrole?

I am supposed to say what is more basic and I ran into a problem. I would like to ask if anyone has any idea what is the correct $\mathrm{p}K_\mathrm{a}\ce{H}$ value of pyrrole. I know it is easy to just google it or open a book to find the answer. I have done that, but got pretty interesting (confusing?) results:

Wikipedia: "Pyrrole is weakly basic, with a conjugate acid $\mathrm{p}K_\mathrm{a}$ of (−3.8)"

Human metabolome database (HMDB): "Pyrrole is a very weak base with a $\mathrm{p}K_\mathrm{a}\ce{H}$ of about (4)"

PubChem: "Pyrrole is a very weak base with a $\mathrm{p}K_\mathrm{a}\ce{H}$ of about (4)"

McMurry 9th edition: "pyrrole - $\mathrm{p}K_\mathrm{a}$ of ammonium ion: (0,4)"

University of Calgary: "pyrrole conjugated acid $\mathrm{p}K_\mathrm{a}$: (-3,8)"