Possibly the most often cited book in the subject of triangle geometry is Nathan Altshiller Court's College Geometry  An Introduction to the Modern Geometry of the Triangle and the Circle (Barnes & Noble, 1952).
Nathan Court was born in Warsaw, Poland, and received the D.Sc. degree in 1911 from the University of Ghent, in Belgium. He became an Assistant Professor of Mathematics at the University of Oklahoma in 1917. In 1919, he became a U.S. citizen and changed his last name to Court, keeping Altshiller as a middle name. He became a full Professor at the University of Oklahoma in 1935 and retired in 1951. Court's two other books are Modern Pure Solid Geometry, Macmillan, 1935, and Mathematics in Fun and in Earnest, New American Library, 1958.

Following is a nearly complete list of Court's mathematical publications in journals:
American Mathematical Monthly
39 (1932) 193199 On the isodynamic points of four spheres
40 (1933) 265269 On two intersecting spheres
41 (1934) 499502 Notes on the orthocentric tetrahedron
43 (1936) 8991 On the Cevian tetrahedron
44 (1937) 317f On mathematical nomenclature
55 (1948) 218221 Notes on cospherical points
56 (1949) 312315 A special tetrahedron
57 (1950) 684f Mathematics "au naturel"
60 (1953) 306310 The semiorthocentric tetrahedron
62 (1955) 5965 Three mutually orthogonal real circles
63 (1956) 714716 Some missing theorems on the anticomplementary tetrahedron
64 (1957) 241247 Three hyperbolas associated with a triangle
66 (1959) 123125 A desmic system of tetrahedrons
67 (1960) 241248 Four intersecting spheres
69 (1962) 614617 Five points in space
Boletin matematico (Buenos Aires)
14 (1941) 230f On the inverse points with respect to a sphere
15 (1942) 1416, 2528 On the anharmonic associates of a point for a triangle and a tetrahedron
15 (1942) 66f A generalization of a theorem of Thebault
28 (1955) 715 Pencils of conics
Bulletin of the American Mathematical Society
48 (1942) 583588 On the theory of the tetrahedron
Duke Mathematical Journal
13 (1946) 123128 A skew quartic associated with a tetrahedron
13 (1946) 3830386 The biratio of the altitudes of a tetrahedron
15 (1948) 4954 Skewly Cevian tetrahedrons
17 (1950) 7581 Semiinverse tetrahedrons
19 (1952) 7174 Isogonal points for a tetrahedron
20 (1953) 417421 Pascal's theorem in space
Mathematical Gazette
36 (1952) Isogonal conjugate points for a triangle
50 (1956) 205207 The harmonic and the polar transformations
Mathematics Student
2 (1934) 107111 Tetrahedral poles and polar planes
3 (1935) 9799 On desmic tetrahedra
10 (1942) 115118 A porism on eleven spheres
20 (1952) 5157 Orthological triangles
24 (1956) 217226 On three intersecting circles
Mathematics Teacher
26 (1933) 4652 The tetrahedron and its circumscribed parallelepiped
41 (1948) 104111 Mathematics in the history of civilization
51 (1958) 369372 Mascheroni constructions
52 (1959) 31f A historical puzzle
53 (1960) 3335 Notes on the centroid
54 (1961) 444452 The problem of Apollonius
55 (1962) 655657 Notes on inversion
Mathesis (twelve articles in French)
National Mathematics Magazine
15 (1941) 271277 On the centroid
17 (1943) 195201 Theorems, their converses, and their extensions
18 (1943) 36 On the Cevians of a triangle
19 (1944) 141146 Elements at infinity in projective geometry
Mathematics Magazine
37 (1964) 1418 Imaginative mathematics
Scientific Monthly
60 (1945) 6366 Geometry and experience
63 (1946) 249256 The motionless arrow
67 (1948) 119123 Is mathematics an exact science?
83 (1956) 2834 Plane geometry and plain logic
Scripta Mathematica
3 (1935) 103111 Art and mathematics
13 (1947) 7985 Mathematical asides
14 (1948) 8597 The tetrahedron and its altitudes
17 (1951) 5564, 190201 Imaginary elements in pure geometry  what they are and what they are not
17 (1951) 147150 Fagnano's problem
19 (1953) 218f The problem of three bisectors
20 (1954) 513, 155164 Desargues and his strange theorem
20 (1954) 113120, 232235 Castillon's problem
22 (1956) 4552 The might and plight of reasoning
22 (1956) 193207 The Cevian chain
Court also published many problem proposals and solutions in the American Mathematical Monthly and other journals.