Deskribapena
Argitaratua:16th ed.-
Alearen deskribapena:Published: Gaitherburg, Md., <1998->
Deskribapen fisikoa:volumes (loose-leaf) : illustrations ; 30 cm
Also issued on CD-ROM.
Argitaratze maiztasuna:Quinquennial, with annual supplements
ISSN:1546-4121
0066-961X