• [1] G. Birkhoff, Bulletin of the American Mathematical Society, vol. 40 (1934), pp. 613-619. MR 1562917
• [2] R. P. Dilworth, Bulletin of the American Mathematical Society, vol. 44 (1938), pp. 262-267.
• [3] W. Krull, Mathematische Zeitschrift, vol. 28 (1928), pp. 481-503. MR 1544973
• [4] O. Ore. Annals of Mathematics, (2), vol. 36 (1935), pp. 406-432. MR 1503232
• [5] M Ward, Annals of Mathematics, (2), vol. 39 (1938), pp. 558-568. MR 1503424
• [6] M. Ward and R. P. Dilworth, Proceedings of the National Academy of Sciences, vol. 24 (1938), pp. 162-164.
• [7] -, these Transactions, vol. 45 (1939), pp. 335-354.

Bibliography

[1]

G. Birkhoff, Bulletin of the American Mathematical Society, vol. 40 (1934), pp. 613-619. MR 1562917

[2]

R. P. Dilworth, Bulletin of the American Mathematical Society, vol. 44 (1938), pp. 262-267.

[3]

W. Krull, Mathematische Zeitschrift, vol. 28 (1928), pp. 481-503. MR 1544973

[4]

O. Ore. Annals of Mathematics, (2), vol. 36 (1935), pp. 406-432. MR 1503232

[5]

M Ward, Annals of Mathematics, (2), vol. 39 (1938), pp. 558-568. MR 1503424

[6]

M. Ward and R. P. Dilworth, Proceedings of the National Academy of Sciences, vol. 24 (1938), pp. 162-164.

[7]

-, these Transactions, vol. 45 (1939), pp. 335-354.