A note on the periodic methanol masers in G9.62+0.20E
  A number of mechanisms to understand the periodic class II methanol masers
associated with some high-mass star forming regions have been proposed in the
past. Two recent proposals, ie. by Parfenov &Sobolev (2014) and Sanna et al.
(2015) have been presented in order to explain the periodic masers in sources
with light curves similar to the methanol masers in G9.62+0.20E. We evaluate to
what extent the proposals and models presented by these authors can explain the
light curve of the methanol masers in G9.62+0.20E. It is argued that neither of
the proposed mechanisms can reproduce the light curves of the methanol masers
in G9.62+0.20E.
