Biographical details can be found here: http://www.gainshare.co.nz/gainshare5.htm
The Glass Museum/Encyclopaedia are virtual resources, as is the Glass Message Board.
Glass publications by Angela Bowey include:
Bagley Glass - the book
by Angela Bowey,
Derek & Betty Parsons
New Zealand Glass
the top 15 essential reference books on glass
An almost impossible task on the basis of what collectors, experts, glass technologists, glass-makers, and glass historians might suggest is essential.
That might be feasible if you use library lending figures for glass books, but would not necessarily include requests for reference library materials.
For a list of materials that I would consider essential, see the bibliography page at www.sklounion.com