Bhojpuri language 

Bhojpuri language is more similar to Awadhi, Braj and Hindi than Magahi or Maithili. And actually i'm unable to provide any citation due to lack of proper categorisation and consideration by authorities and so there's no published record. But if you want, i can prove my point.. Better let me do.
For example, if i've to say, "What is you name?" in bhojpuri, it'd be, "tahaar naam kaa ha?" in awadhi, it is, "tahaar naam kaa hai?" in hindi, it is, "tumhara naam kya hai?" in braj, it is, "tahaar naam kaa hai", and in magadhi, it is "tor naam ki helthi?" in maithili, it'd be, "aahank naam ki chhe?". Now decision is all upon you.
And one thing, if there's no evidence on a particular point on net then the view of native speaker can be, should be and must be accepted.
Thanks.