the wordpress functoin get_author_posts_url($id) returns the url you need.
Something like this should work:
<?php $author_id1 = 1; $author_id2 = 2; $author_id3 = 3; ?>
<div><?php the_author_meta( 'display_name', $author_id1 ); ?> <a href="<?php echo get_author_posts_url($author_id1); ?>">Read more</a></div>
<div><?php the_author_meta( 'display_name', $author_id2 ); ?> <a href="<?php echo get_author_posts_url($author_id2); ?>">Read more</a></div>
<div><?php the_author_meta( 'display_name', $author_id3 ); ?> <a href="<?php echo get_author_posts_url($author_id3); ?>">Read more</a></div>
where 1, 2, and 3 are the author ids of your authors.
EDIT: You are right in assuming this falls outside "the Loop". If you don't know the IDs of the authors, you can get them in this way: http://wordpress.org/support/topic/getting-user-id-from-username