1. C arrier G. F . 1956 S ound tran sm issio n from a tu b e w ith flow. appl. M ath. 13 457- 461.
2. Theorie der L uftschall D am pfung im R ech teck k an al m itschluckender W an d u n d d as sich dabei ergebendehochste D am pfungs;Crem L.;Acoustica,1953
3. Jo n es D. S. 1964 The theory of electromagnetism. L o ndon: P ergam on Press.
4. K an to ro v ich L. V. & K ry lo v V. I. 1958 A pproxim ate methods of higher analysis. G roningen T he N e th e rla n d s: P . N oordhoff.
5. K ran zer H . C. & R adlow J . 1965 An asy m p to tic m eth o d for solving p e rtu rb e d W ien er-H o p f problem s. J . M ath. M ech. 14 41- 60.