B9IV

MK73 and GrayNstars list alf Del (HR 7906) as their B9IV standard

JM53 lists a non-standard 134 Tau (HD 38899) as B9IV.  

GarrisonGray94 list 134 Tau as their low-vsini B9IV standard, and alf
Del as their high-vsini B9IV standard.

Houk88 adopts 134 Tau (= HR 2010, HD 38899) from JM53 as their B9IV standard.

GrayNstars lists Alf Del as their B9IV Steward Obs. and DSO standard. 

# Primary Standard
HD 38899 = HR 2010 = 134 Tau 
  B9IV: JM53,Houk88,GarrisonGray94(low-vsini stan.)

HR 7906 = Alf Del 
  B9IVn: MK73,GarrisonGray94(high-vsini stan.)