The following formula is involved in the calculation of book values per share for preferred stock:

Book value per share of preferred stock:
where L is the liquidation value of preferred stock, D is the amount of preferred dividends in arrears, and S is the number of preferred shares outstanding.

The following references can be used to cite this book value per share calculator for preferred stock:
 Soper, D.S. (2018) "Book Value Per Share Calculator for Preferred Stock (Online Software)", http://www.danielsoper.com/fincalc. 
 Bragg, S. (2012). "Business Ratios and Formulas: A Comprehensive Guide", Hoboken, NJ: John Wiley & Sons. 