question about Shankara

[Madhav Deshpande]

        While we are discussing Shankara tradition, I would like to know
the source of two quotations.  The first one reads: zankaraH zankaraH
sAkshAd vyAso nArAyaNo hariH.  The second reads: caturbhiH saha zishyais
tu zankaro'vatarishyati.  These occur as citations in a text that I am
currently translating.  I have not been able to find their source.  The
second quotation is qualified with iti ArshavAkyAt.  This probably refers
to a Purana as its source.
        With best wishes,
                                        Madhav Deshpande