Added Python's Excel Integration references

README.md

@@ -98,6 +98,19 @@ A curated list of insanely awesome libraries, packages and resources for Quants
 - [after-hours](https://github.com/datawrestler/after-hours) - Obtain pre market and after hours stock prices for a given symbol
 - [bronto-python](https://github.com/Scotts-Marketplace/bronto-python/) - Bronto API Integration for Python
 
+### Excel Integration
+
+- [xlwings](http://xlwings.org) - Make Excel fly with Python!
+- [openpyxl](https://openpyxl.readthedocs.org/en/latest/) - Read/Write Excel 2007 xlsx/xlsm files
+- [xlrd](https://github.com/python-excel/xlrd) - Library for developers to extract data from Microsoft Excel spreadsheet files
+- [xlsxwriter](https://xlsxwriter.readthedocs.org/) - Write files in the Excel 2007+ XLSX file format
+- [xlwt](https://github.com/python-excel/xlwt) - Library to create spreadsheet files compatible with MS Excel 97/2000/XP/2003 XLS files, on any platform.
+- [DataNitro](https://datanitro.com/) - DataNitro also offers full-featured Python-Excel integration, including UDFs. Trial downloads are available, but users must purchase a license.
+- [ExcelPython](https://github.com/ericremoreynolds/excelpython) - An open source, easy to use interface for calling Python code from Excel.
+- [xlloop](http://xlloop.sourceforge.net) - XLLoop is an open source framework for implementing Excel user-defined functions (UDFs) on a centralised server (a function server).
+- [expy](http://www.bnikolic.co.uk/expy/expy.html) - The ExPy add-in allows easy use of Python directly from within an Microsoft Excel spreadsheet, both to execute arbitrary code and to define new Excel functions.
+- [pyxll](https://www.pyxll.com) - PyXLL is an Excel add-in that enables you to extend Excel using nothing but Python code.
+
 ## R
 
 ### Numerical Libraries & Data Structures