Can anyone help me with a good reference to 14 -century SAyaNa and his
brother(?) MAdhava , their relation, any information concerning their
historical setting and whatever could be usefull when evaluating
SAyaNa's preface to his (?) commentary
on RV. What is of interest to me in particular is the following:

1) Were SAyaNa and MAdhava realy brothers ?
2) What is the source of our knowledge concerning S &/or M serving as
    ministers on Vijayanagara courts of Bukka I & Harihara II
3) How can one understand the very beginning of S's Preface whare it is
    said that it is MAdhava who is going to explain (vedArtham vaktum) the
   aim/meaning of the Veda
4) If S was influenced by his brother's teachings can one look on supposedly
   PM ideas introduced along with Jaimini sutras as tainted by Vedantic
   thought?
4) Could there be any possibility of an influence of another type of
   ideas on SAyaNa through his brother holding the post of the Head of
   SmArta MaTh at ZRNgeri