Languages:
L     -	  Latin
ME    -	  Middle English
OE    -	  Old English
OF    -	  Old French
OI    -	  Old Irish
ON    -	  Old Norse
X     -	  unkown language (the origin of a given verb is obscure)

Verbs:
A     -	  anomalous 
D     -	  defective
I     -	  irregular
M     -	  mixed
MAD   -	  mixed, anomalous and defective
R     -	  regular
RI    -   shifted

Symbols:
[]    -	  enclose the number indicating the source from which
	  the infinitive form has been collected, and thus:
            [1] - A Treatise on the Astrolabe by Chaucer 
	    [2] - A Chaucer Glossary by Davis, et al.
	    [3] - Oxford English Dictionary on CD-ROM by Murray et al.
	    [4] - Middle English Dictionary by Kurath and Kuhn