[1] L. S. Bгown, W. I. Weisgerber: Vacuum polarization in uniform non-Abelian gauge fields. Nucl. Phys. B 157 (1979), 285-326.
[2] M. Goto, F. D. Gгosshans: 
Semisimple Lie Algebras. M. Dekker, New York, 1978. 
MR 0573070[3] C. H. Gu: 
On parallel Yang-Mills fields. in: S.-T. Yau (ed.), Seminaг on Differential Geometгy, Princeton Univ. Pгess, 1982, p. 443-453. 
MR 0645752 | 
Zbl 0482.53035[4] H. Leutwyleг: Vacuum fluctuations surrounding soft gluon fields. Phys. Lett. 96 B (1980), 154-158.
[5] H. Leutwyler: Constant gauge fields and their quantum fluctuations. Nucl. Phys. B 179 (1981), 129-170.
[6] P. Minkowski: On the ground-state expectation value of the field strength bilinear in gauge theories and constant classical fields. Nucl. Phys. B 177 (1981), 203-217.
[7] N. K. Nielsen, P. Olesen: 
An unstable Yang-Mills field mode. Nucl. Phys. B 144 (1978), 376-396. 
MR 0511496[8] F. Palumbo: Constant gauge field configurations and Galilei gauge theories. Phys. Lett. 137 B (1984), 404-406.
[9] R. Schimming: 
Huygens-type multicomponent hyperbolic differential equations of second order. (in Russian), Ukrainsk. Mat. J. 29 (1977), 351-363. 
MR 0458514[10] R. Schimming: 
Das Huygenssche Prinzip bei linearen hyperbolischen Differentialgleichungen zweiter Ordnung für allgemeine Felder. Beiträge zur Analysis 11 (1978), 45-90. 
MR 0502738[11] R. Schimming: Differential operators with Laplace-like principal part and logarithm-free elementary solution. foгthcoming paper.
[12] P. van Baal: 
SU(N) Yang-Mills Solutions with Constant Field Strength on $T^4$. Commun. Math. Phys. 94 (1984), 397-419. 
MR 0763387