added references to __init__'s docstring
added references to __init__'s docstring

kris-singh/pgmpy,pgmpy/pgmpy,ankurankan/pgmpy,abinashpanda/pgmpy,liquidmetal/pgmpy,sandeepkrjha/pgmpy,palashahuja/pgmpy,jhonatanoliveira/pgmpy,ankurankan/pgmpy,liquidmetal/pgmpy,anaviltripathi/pgmpy,sandeepkrjha/pgmpy,abinashpanda/pgmpy,yashu-seth/pgmpy,jhonatanoliveira/pgmpy,palashahuja/pgmpy,vivek425ster/pgmpy,khalibartan/pgmpy,yashu-seth/pgmpy,khalibartan/pgmpy,anaviltripathi/pgmpy,pratyakshs/pgmpy,pgmpy/pgmpy,pratyakshs/pgmpy,kris-singh/pgmpy,vivek425ster/pgmpy