Mutual inductance for 2 coils seperated by a distance

HI,

i have done applying ac current-time dependent analysis in a coil and analysed the magnetic flux density with the theortical equation of biot savart law for circular coil. Now i have to calculate mutual inductance and induced current of secondary coil by placing them apart a distance with same radius of the coil for the reciever as the transmitter coil.

so i have checked a model library file which gives mutual inductance for coplanar arrangement coils. i need mutual inductance formula for coils which is placed apart at distance parallel to it.

Any one who have done this earlier can help me ..
thanks
Rajesh