The paper is based upon a study on the citations in the Science Citation Index (1992-2002) to the e-print archives of Los Alamos National Laboratory on the subject categories 'nucl-th' (nuclear theory) and 'nucl-ex' (nuclear experiment). The trend of growth of e-print archives and citing pattern of e-print archives are studied. The paper has also identified the highly cited e-print archives and the highly citing journals. The study shows the growing use of e-print archives as the knowledge-generating system for fast communication of results and ideas, and their quick use.