Table 3.

Knowledge representation: the main types of variants are “standard” (std) and “regular expression” (regexp)

Variant type	Description	Example (GER)	Example (ENG)	Compound
std	simple string	Aortenklappe	aortic valve
std	simple string	Insuffizienz	regurgitation
std	simple string	Aortenklappeninsuffizienz	aortic valve regurgitation	oa
regexp	regular expression	|(= s*)?[0-9]+|	|(= s*)?[0-9]+|

Each entry can optionally be specified as an object-attribute (oa) compound, or an attribute-value (av) compound