  Exact solutions are reported for a periodic assembly of bubbles steadily
co-travelling in a Hele-Shaw channel. The solutions are obtained as conformal
mappings from a multiply connected circular domain in an auxiliary complex
plane to the flow region in a period cell. The conformal mappings are
constructed using the generalized Schwarz-Christoffel formula for multiply
connected polygonal domains in terms of products of Schottky-Klein prime
functions. It is shown that previous solutions for multiple steady bubbles in a
Hele-Shaw cell are all particular cases of the solutions described herein.
Examples of specific bubble configurations are discussed.
