b.  Type  T o:  at  the  margin  on  the first  line  under  the  from  block.  Four  spaces follow  the  colon. c.  Whenever  practical,  include  a  code  or person’s  title  in  parentheses  right  after  the activity’s   name.   Add   the   word   Code   before codes that start with numbers. A code that starts with  a  letter  is  readily  identifiable  as  a  code without  the  added  word. 11.  Via  Block a.  List  commanding  officers  in  the  via block  as  if  composing  a  from  or  to  block.  Give a  complete  mailing  address,  ZIP  Code  included, if  you  want  it  for  a  record. b.  Type  Via:  at  the  left  margin  on  the first line below the to block. Three spaces follow the  colon. c. Number via addressees if you list two or   more.   Routing   starts   with   the   addressee listed   first.   When   going   down   a   chain   of command,   first   list   the   next   lower   echelon. When  going  up  your  chain  of  command,  first list  the  next  higher  echelon. d.  Follow  your  chain  of  command  when corresponding  on  substantive  matters  such  as command   decisions,   policy   issues,   and   official recommendations.   Such   routing   keeps   inter- mediate commands informed and allows them to comment  or  approve.  For  variations  see  SEC- NAVINST  5216.5C. 12.  Subject a. Craft the subject to make it genuinely informative. b.  Type  Subj:  at  the  left  margin  on the  second  line  under  the  last  line  of  the previous  heading.  Two  spaces  follow  the  colon. Use  normal  word  order.  Capitalize  every  letter after   the   colon.   When   a   subject   appears elsewhere  in  a  letter,  capitalize  the  first,  last, and  other  key  words  as  if  you  were  writing  a book  title. 13.  References a.  Use  only  those  references  that  bear directly   on   the   subject   at   hand.   Avoid   un- necessary  or  complicated  references.  Many  letters need   no   references   at   all,   while   others   are complete   with   a   reference   to   only   the   latest communication. b.  Be  sure  to  mention  in  the  text  any reference   cited   in   the   reference   block.   List references  in  the  reference  block  by  following the  order  of  their  appearance  in  the  text. c.   Avoid   most   NOTAL   references.   A NOTAL—not to all—reference is a document that some addressees or all of them neither hold nor need.  Work  to  cite  directives,  correspondence,  and messages held by all addressees. For alternatives to NOTAL  references,  see  SECNAVINST  5216,5C. d.  Type  Ref:  at  the  left  margin  on  the second  line  below  the  subject.  Use  a  lower-case letter  in  parentheses  before  the  description  of every reference, even a single one. Three spaces follow  the  colon.  One  space  follows  the  closing parenthesis.  When  referencing  correspondence, include:   (1)   SNDL   short   title   of   originator, (2)  type  of  correspondence  (ltr,  spltr,  or  memo), (3)  SSIC,  (4)  originator’s  code  by  itself  or  in  a serial   number,   and   (5)   date.   SECNAVINST 5216.5C  also  shows  how  to  reference  messages, endorsements,  telephone  conversations,  instruc- tions,  notices,  forms,  reports,  and  publications. 14.  Enclosures a. Try to keep letters short, down to one page  whenever  possible,  and  use  enclosures for lengthy explanations that cannot be avoided. List enclosures in the order of their appearance in  the  text.  In  the  text  spell  out  the  word enclosure. Describe an enclosure like a reference. b.  Type  Encl:  at  the  left  margin  on the  second  line  below  the  last  line  of  the previous heading. Use a number in parentheses before the description of every enclosure, even a single  one.  Two  spaces  follow  the  colon.  One space  follows  the  closing  parenthesis. c.  Normally,  send  one  copy  of  the  basic letter   plus   any   enclosures   to   all   addressees. Avoid sending an enclosure if an addressee has it already or if bulk or other factors make furnishing it  impractical. d.  When  sending  more  than  one  copy  of an enclosure to all addressees, note the quantity in parentheses after the enclosure’s description. For  variations  in  the  distribution  of  enclosures to copy-to and via addressees, see SECNAVINST 5216.5C. e.  Mark  an  enclosure  on  the  first  page only, in the lower right corner, whether the text is arranged normally or lengthwise. Type, stamp, or  write  Encl  plus  its  number  in  parentheses. Pencil may be used so an addressee can remove the  marking  easily  should  the  enclosure  be  needed 10-6