Bulat is not without faults. I notice, for example, that the coverage of colour variations for Kyiv II overprints is not consistent: sometimes known variants are listed, sometimes not. Listing of inverted overprints is also not consistent.
This is minor. More important is the large number of typographical errors. Where these involve pricing, they can often be corrected by referring back to Seichter's catalog: in general, Bulat's $ price is arrived at by halving the Deutschmark figure in Seichter. So if Seichter has 100 and Bulat has $5 that's going to be a typographical error for $50
One of Bulat's special interests was in the Tridents of Poltava. He did fresh work on the 25 - cliche handstamps and this is presented at pages 50 - 73. Some of the panes on which Bulat's work is based will appear for sale in the upcoming Corinphila auction of Dr Ron Zelonka's collection.
But the pricing of these panes is a mess. For example, a single copy of a 2 kopeck imperforate with a Type I handstamp in violet is priced at $10 (Bulat 963). But a complete pane of 25 is priced at $50 (Bulat 909,913, 927). The $50 must be a mis-print for $500 on the basis that if a single is worth $10 then a pane of 25 is worth a minimum of $250, doubled to recognise the scarcity of the 25-cliche handstamps in complete units.