A4V

no A4V dagger type (Garrison94), but HD 97603 = Del Leo is probably best.
I've found that 49 Ori (HD 37507) may be a good candidate A4V standard -- we should 
get a spectrum of it.

Cowley69 used Del Leo (HD 97603) as their A4V standard.

Morgan65 did not classify any Hyads as A4V. 


For Hipparcos d < 75 pc sample:
<B-V>  = 0.160 (N=17)
<V-Ic> = 0.180 (N=17)
<V-Ks> = 0.401 (+-0.038 sem, +-0.099 stdev; N=11)

# No standard

Morgan65,MK73,GrayGarrison89,GrayAtlas do not list A4V standards

Skiff08 did not flag any stars as A4V standards. 

While GrayGarrison89 did not list A4V standards, they did classify 9
stars as A4V or A4Vn. The brightest two examples of both were HD 37507
(= 49 Ori) and HD 59037 (= 64 Gem) (both A4Vn), and HD 11636 (iot Ari)
and HD 184006 (iot^2 Cyg) (both A4V).

Gray01/03/06 lists *1* nearby A4V dwarf (HIP 113368 = Fomalhaut). As
Fomalhaut is *the* A3V anchor, I do not believe that its BVI colors
are typical for A4V dwarf stars! Argggh!

# Standard

HD 97603 = Del Leo = HR 4357 
  A4V: HoukStand,JM53,Cowley69(stan),Jaschek78,Garcia89,Abt95,Levato78
  A4IV: GrayGarrison89
  A5IV(n): Gray03
  This star is a bit bluer than the A4V mean B-V (0.l60)
  A4V; B-V[HIP]=0.128+-0.014

# Weak Standard

HD 11636 = Bet Ari = 6 Ari = HR 553 = GJ 80
  A5V: MK43,JM53,Jaschek64(all),Morgan65,Jaschek78,Garcia89
  kA4hA5mA5Va: Gray03 (i.e. an A5Va!)
  A5IV: Barry70
  A4V: Abt85,GrayGarrison89,Garrison96,Abt95
  A4: Olsen69
  A5: Cannon
  Basically morphed from A5 under Morgan to A4 (Abt,Gray,Garrison), *despite*
  Morgan65 listing bet Ari as a "fundamental A5 classification standard" w/ del Cas
  i.e. "Its a fundamental standard until someone comes along and changes it..."
  B-V(HIP)=0.165, dMv=-0.53 (color is closer to Houk's mean A4V B-V color)
  I'm going to stick to *A5V* following MK43,JM53,Morgan65,Gray03

# Candidate Standard

HD 37507 = HR 1937 = 49 Ori = HIP 26563
  A4V: Jaschek64(both; "SB"),Cowley69,GrayGarrison89(A4Vn)
  A4IV: Slettebak55,Abt95
  A2V: Houk99
  Never previously considered a standard. 
  Houk99 comments: "37507: HR 1937; 49 ORI; vSINi=185"
  Remarkable that *all* of the references in Skiff09 (N=4) list it as an A4 subclass.
  Houk99 does call it an A2V, however. Using the revised Hipparcos astrometry,
  I find the star to have Mv=1.52 or dMv = -0.23 (V=4.77; B-V=0.139; V-I=0.16+-0.02; plx=22.42mas)
  Stars B-V and V-I are only 0.02 bluer than the median B-V and V-I colors for the
  d<75 pc Hipparcos sample. Hence the color-mag data are consistent with a A4V. 
  This may be a useful candidate "A4Vn" standard (agreement in subclass by
  Slettebak, Abt, Jascheks, Gray, Garrison, and Cowley)


# Other Stars
HD 59037 = HR 2857 = 64 Gem  (V=5.1)
  A4V: Cowley69,GrayGarrison89(A4Vn)
  A2.5V: Abt95
  A6V: Osawa59
  Never considered a standard by anyone. Not very good agreement among authors (although
  Cowley and GrayGarrison89 agree). Probably not a good candidate standard.