1. (a) and ?Engineering Principles of Plasticating Extrusion,? Van Nostrand Reinhold Book Co., New York, N. Y. (1970). p. 79,
2. (b) and ?Engineering Principles of Plasticating Extrusion,? Van Nostrand Reinhold Book Co., New York, N. Y. (1970). p. 257,
3. (c) and ?Engineering Principles of Plasticating Extrusion,? Van Nostrand Reinhold Book Co., New York, N. Y. (1970). p. 232,
4. (d) and ?Engineering Principles of Plasticating Extrusion,? Van Nostrand Reinhold Book Co., New York, N. Y. (1970). p. 217.