appendix r r e f e r e n c e s 1) g. m. birtwistle "demos - discrete event modelling on simula", macmillan, 1979. 2) g. m. birtwistle, o. j. dahl, b. myrhaug, and k. nygaard "simula begin", studentlitteratur, 1973. 3) a. clementson "ecsl manual", university of birmingham, england, 1973. 4) o. j. dahl and k. nygaard "simula 67 common base language", norwegian computing centre, oslo, norway, 2nd edition, 1970. 5) d. y. downham and f. d. k. roberts "multiplicative congruential pseudo-random number generators", computer journal, 10(1), 1967, pp. 74-77. 6) a. t. fuller "the period of pseudo-random numbers generated by lehmer's congruential method", computer journal, 19(2), 1976, pp. 173-177. 7) m. ohlin "next random - a method of fast access to any number in the random generator cycle", simula newsletter, 6(2), 1977, pp. 18-20. 8) j. vaucher "simulation data structures using simula 67", proc. winter simulation conference, 1971, pp. 255-260.