J. H. Conway and R. K. Guy, The Book of Numbers,
pp. 187-189, Springer-Verlag (Copernicus), New York, 1996.
ISBN 0-387-97993-X.
F. G. Frobenius, Über die Markoffschen Zahlen,
Sitzungsberichte der Königlich Preußischen Akadamie der
Wissenschaften zu Berlin, (1913), pp. 458-487.
This is an extensive and interesting paper. The
original journal may be hard to locate; a copy of the paper
appears as chapter 96 in Band III of Ferdinand Georg
Frobenius Gesammelte Abhandlungen,
Springer-Verlag, Berlin, 1968.
A. A. Markoff, Sur les formes binaires indéfinies,
Math. Ann. 17 (1880), pp. 379-399.
G. Rosenberger, The Uniqueness of the Markoff Numbers, Mathematics
of Computation, Volume 30, Number 134, April 1976, pp. 361-365.
This paper claimed to prove the unicity conjecture, but was flawed
as pointed out by R. Bumby in MR53 (1977) 280.
Should Markoff be spelled -off or -ov?
"Markoff" is more often used when discussing his
work in number theory (e.g., Markoff numbers);
"Markov" tends to be used when discussing his
work in probability (e.g. Markov chains).