Patent classifications
E
FIXED CONSTRUCTIONS
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E04
BUILDING
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E04D
ROOF COVERINGS; SKY-LIGHTS; GUTTERS; ROOF-WORKING TOOLS
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3/00
Roof covering by making use of flat or curved slabs or stiff sheets
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E04D3/02
of plane slabs, slates, or sheets, or in which the cross-section is unimportant
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E04D3/04
of concrete or ceramics
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