B7V

There is no B7V dagger standard, but HD 21071 appears to be the best standard.

Lesh68 lists 49 Eri as their B7V standard. 

Skiff08 lists only one B7V standard: HD 21071 (MK78)

Cowley72 lists Alf Leo = HD 87901 as their B7V standard. 

For two acceptable B7V standards:
<B-V>(B7V) = -0.140 (+-0.010 sem, +-0.013 stdev; N=2 standards)
<U-B>(B7V) = -0.489 (+-0.038 sem, +-0.054 stdev; N=2 standards)

# No Standard
Houk, MK43, Garrison67, Cowley69, Hiltner69, MK73, Garrison77,
Garrison79, and GrayAtlas do not list a B7V standard. GarrisonGray94 only
cover B8-B9, so no B7 standard is listed. 

# Primary Standards
HD 21071 = HR 1029 = Cl Melotte 20 675 (alpha Per cluster)
  B7V: Heckman58(B7),Morgan71,MK78,Jaschek78,Abt78(B7Vsn),Keenan85,Garcia89,GarrisonGray94
  B5: Petrie69,Cannon
  B5IV: Lesh68
  B6V: Roman50,Jaschek64
  Appears to be a decent standard; consistently B7V after Morgan71
  M91: V=6.070+-0.014, B-V=-0.076+-0.005, U-B=-0.483+-0.012 
  =>QBV=> (B-V)o=-0.149, (U-B)o=-0.527, E(B-V)= 0.073, T=14952.

# Secondary Standard
HD 29335 = 49 Eri = HR 1469
  B7V: Slettebak55,Jaschek64,Kennedy83(Lesh68(stan))
  B5: Cannon
  B8IV: Houk99 
  Houk99 says vsini=120 km/s.
  Slettebak and Lesh both agree B7V. 
  M91: V=5.307, B-V=-0.128, U-B=-0.455
  QBV: (B-V)o=-0.130, (U-B)o=-0.451, E(B-V)= 0.002

# Weak standard
HD 87901 = Alf Leo = Regulus = 32 Leo = HR 3982 = GJ 9316A
  B7V: JM53,Osawa59,Jaschek64(major. are B7V),Cowley72(stan),Jaschek78(Murphy69),Garcia89,Garrison96(B7Vn)
  B8IVn: Gray03 
  B8III: Williams36
  B8V: MK43,GarrisonGray94(B8Vnn),Palmer68(B8Vn),Cannon(B8)
  Oscillates between B7V and B8V.in the literature. 

# Other
Alf Gru
  B7Vn: Garrison96
  Ranges from B5-B7 in the other literature