There are four types of cover forms (knives):
HP cover form 1.jpg (15074 bytes) HP cover form 2.jpg (9725 bytes) HP cover form 3.jpg (12774 bytes) no picture available
superior flap: rounded
inferior flap: rounded
side flaps: corners one above the other		 inferior flap: rounded inferior flap: straight superior flap: big (83 mm), rounded; inferior flap: rounded
side flaps: not overlapping
# C 1 # C 2 # C 3 # C 4
There are three types of indicia.
Wertzeicheneindruck U 42.jpg (12925 bytes) Wertzeicheneindruck U 43.jpg (25277 bytes) Wertzeicheneindruck U 47.jpg (12636 bytes)
# I 1 (U 42) # I 2 (U 43) # I 3 (U 47)
BULGARIA
001 1958 National Spartakiad 1958 - 1959
official entire with cover form # C 1
purple red indicium # I 1
white paper
20 Stotinki		 HP 01 VS.jpg (23645 bytes)
MICHEL U 42 I  
There might exist a colour variety of this item printed in black colour. I can only show an example showing the sport of Basketball, but it is well possible that it also exists with the sport of Volleyball. HP 01 VS in black colour Basketball.jpg (36997 bytes)
002 x 1958 National Spartakiad 1958 - 1959
official entire with cover form # C 2
green indicium # I 1
white paper
20 Stotinki		 HP 02 VS green.jpg (28916 bytes) HP 02 VS darkgreen.jpg (29653 bytes)
green darkgreen
MICHEL U 42 II a exists in different shades of green
003 x 1958 National Spartakiad 1958 - 1959
official entire with cover form # C 2
brown indicium # I 1
white paper
20 Stotinki
MICHEL U 42 II b exists in different shades of brown
004 1958 National Spartakiad 1958 - 1959
official entire with cover form # C 2
red indicium # I 1
white paper
20 Stotinki
MICHEL U 42 II c exists in different shades of red
005 x 1958 National Spartakiad 1958 - 1959
official entire with cover form # C 4
olive green indicium # I 1
blue paper
20 Stotinki		 no picture available
MICHEL U 43  
I have no image with the sport of Volleyball of this item, but another one with the sport of Boxing. HP 05 VS Boxing.jpg (26970 bytes)
006 x 1959 National Spartakiad 1958 - 1959
official entire with cover form # C 4
green indicium # I 2
16 Stotinki		 HP 06 VS.jpg (34609 bytes)
MICHEL U 45  
007 1959 National Spartakiad 1958 - 1959
official entire with cover form # C 2
brown indicium # I 3
white paper
20 Stotinki		 HP 07 VS.jpg (27303 bytes)
MICHEL U 47 I a exists in different shades of brown
008 1959 National Spartakiad 1958 - 1959
official entire with cover form # C 2
purple red indicium # I 3
white paper
20 Stotinki		 HP 08 VS.jpg (22898 bytes)
MICHEL U 47 I b  
009 x 1959 National Spartakiad 1958 - 1959
official entire with cover form # C 2
lilac indicium # I 3
white paper
20 Stotinki		 no picture available
MICHEL U 47 I c  
010 x 1959 National Spartakiad 1958 - 1959
official entire with cover form # C 3
brown indicium # I 3
grey paper
20 Stotinki		 HP 10 VS.jpg (63198 bytes) HP 10 VS indicium further right.jpg (39734 bytes)
indicium in normal position indicium and address lines further right
MICHEL U 47 II a exists in different shades of brown
011 1959 National Spartakiad 1958 - 1959
official entire with cover form # C 3
red indicium # I 3
grey paper
20 Stotinki		 HP 11 VS.jpg (24111 bytes)
MICHEL U 47 II b exists in different shades of red
012 x 1959 National Spartakiad 1958 - 1959
official entire with cover form # C 3
bluish green indicium # I 3
grey paper
20 Stotinki		 no picture available
MICHEL U 47 II c  

Here is some additional and general information about postal stationery items from this period. It was submitted by Mr. Richard Stevens, USA:

First, a little background about these Bulgarian stamped envelopes. Apparently, beginning in 1955, there was a government policy to produce envelopes in a wide variety of colors, as well as pictures, indicia, etc. No public announcement was made of what was produced, and the shipments were arranged so that no one post office received more than a random selection of the various varieties.
This policy remained in effect, to a greater or lesser degree until the early 1970s. As a result, no official record exists of what was issued. As there were few collectors, no attempt was made to catalog these issues until 1979, when a catalog was published in Bulgaria, in conjunction with the International Philatelic Exhibition in Sofia. This catalog was a good start, and certainly far superior to the admittedly incomplete listing in Higgins & Gage. However, there are many omissions, particularly of colors, and even of entire issues. Currently, the Bulgarian dealers dismiss this catalog as having "many mistakes". The Michel catalog listing is almost entirely based on this Bulgarian catalog, with some rearrangement, and some simplification in the color varieties; although I still find the Michel catalog has many instances where it is unclear what their color descriptions mean.

The Bulgarian catalog lists the following Volleyball envelopes:

001 - 004: Indicium 1, white paper, Knife 4

a brown b red-brown
v lilac-brown g violet-brown
d red e brown-red
zh green z olive-green
i dark olive-green k dark green
l red-violett m red-violet in Knife 5

005: Indicium 1, blue paper, Knife 4

olive-green

007 - 009: Indicium 3, white paper, Knife 4

a brown b light brown
v dark brown g violet-red
d lilac-brown e red-brown
zh lilac

010 - 012: Indicium 3, white paper, Knife 6

a red b orange-red
v dark brown g lilac-brown
d blue-green

As you can see, Michel reduced the number of colors significantly.

The envelopes with indicium 2 are omitted entirely by the Bulgarian catalog.

I am not sure what all the colors listed in the Bulgarian catalog are supposed to be. Knowing what I find in other issues, I don't pay much attention to the colors listed, but simply try to establish my own color varieties. I find that I must try to standardize by using sunlight to observe the colors. Obviously, one cannot make close judgments from a computer scan.

Richard Stevens, Greendell, NJ, USA